Role of growth factors, cytokines, and their receptors in the pathogenesis of psoriasis

Structural and functional imaging of psoriasis for severity assessment and quantitative monitoring of treatment response using high-resolution optoacoustic imaging

Psoriasis is a chronic inflammatory skin disease, characterized by thick scaly plaques. It imposes a notable disease burden with varying levels of severity affecting the quality of life significantly. Current disease severity assessment relies on semi-objective visual inspection based on the Psoriasis Area and Severity index (PASI) score that might not be sensitive to sub-clinical changes. Histology of psoriasis skin lesions necessitate invasive skin biopsies. This indicates an unmet need for a non-invasive, objective and quantitative approach to assess disease severity serially. Herein, we employ multispectral Raster-Scanning Optoacoustic Mesoscopy (ms-RSOM) derived structural and microvascular functional imaging metrics to examine the lesional and non-lesional skin in psoriasis subjects across different severities and also evaluate the treatment outcome in a subject with topical steroids and biologics, such as adalimumab. ms-RSOM derived structural metrics like epidermal thickness and total blood volume (TBV) and microvascular functional information such as oxygen saturation (sO2) are evaluated by spectrally resolving the endogenous chromophores like melanin, oxy-, and deoxy-hemoglobin. Initial findings reveal an elevated sO2 and TBV with severity in lesional and non-lesional psoriasis skin, thus representing increasing inflammation. An increase in epidermal thickness is also noted with the degree of severity, corresponding to the inflammation and increased abnormal cell growth. As a marker to evaluate the treatment response, we observed a decrease in epidermal thickness, sO2, and TBV in a psoriasis patient post-treatment, which is consistent with the decrease in the PASI score from 4.1 to 1.9. We envision that ms-RSOM has a huge potential to be translated into routine clinical setting for the diagnosis of severity and assessment of treatment monitoring in psoriasis subjects.

Cytokines in psoriasis: From pathogenesis to targeted therapy

Psoriasis is a multifactorial disease that affects 0.84% of the global population and it can be associated with disabling comorbidities. As patients present with thick scaly lesions, psoriasis was long believed to be a disorder of keratinocytes. Psoriasis is now understood to be the outcome of the interaction between immunological and environmental factors in individuals with genetic predisposition. While it was initially thought to be solely mediated by cytokines of type-1 immunity, namely interferon-γ, interleukin-2, and interleukin-12 because it responds very well to cyclosporine, a reversible IL-2 inhibitor; the discovery of Th-17 cells advanced the understanding of the disease and helped the development of biological therapy. This article aims to provide a comprehensive review of the role of cytokines in psoriasis, highlighting areas of controversy and identifying the connection between cytokine imbalance and disease manifestations. It also presents the approved targeted treatments for psoriasis and those currently under investigation.

Pyruvate Kinase M2 Mediates Glycolysis Contributes to Psoriasis by Promoting Keratinocyte Proliferation

Psoriasis is characterized by keratinocyte proliferation and immune cell infiltration. M2 isoform of pyruvate kinase (PKM2) was reported to have an important role in cell proliferation, which is a rate-limiting enzyme that regulates the final step of glycolysis. However, how PKM2 regulates cell metabolism and proliferation in psoriatic keratinocytes is still poorly understood. Interestingly, we found that PKM2 was highly expressed in psoriatic epidermis from patients and mouse models. PKM2 overexpression promoted keratinocyte glycolytic metabolism while knockdown inhibited keratinocyte proliferation and glycolysis. Mice lacking PKM2 specifically in keratinocytes, pharmacological inhibition of PKM2 or glycolysis inhibited keratinocyte proliferation and showed obvious remission in an imiquimod-induced psoriatic mouse model. Moreover, the inhibitor of the EGF-receptor blocked EGF-stimulated PKM2 expression and glycolysis in keratinocytes. We identify PKM2 as an upregulated gene in psoriasis. PKM2 is essential in keratinocyte over-proliferation and may represent a therapeutic target for psoriasis.

Nod-Like Receptors in Host Defence and Disease at the Epidermal Barrier

The nucleotide-binding domain and leucine-rich-repeat-containing family (NLRs) (sometimes called the NOD-like receptors, though the family contains few bona fide receptors) are a superfamily of multidomain-containing proteins that detect cellular stress and microbial infection. They constitute a critical arm of the innate immune response, though their functions are not restricted to pathogen recognition and members engage in controlling inflammasome activation, antigen-presentation, transcriptional regulation, cell death and also embryogenesis. NLRs are found from basal metazoans to plants, to zebrafish, mice and humans though functions of individual members can vary from species to species. NLRs also display highly wide-ranging tissue expression. Here, we discuss the importance of NLRs to the immune response at the epidermal barrier and summarise the known role of individual family members in the pathogenesis of skin disease.

TGF-β1 Gene Polymorphism and Its Correlation with Serum Level of TGF-β1 in Psoriasis Vulgaris Among Iraqi People

PURPOSE

Many cytokines have been implicated in the pathogenesis of psoriasis, among these the transforming growth factor-beta 1 (TGF-β1) can be endorsed by different mechanisms besides inhibiting keratinocytes proliferation. The role of genetic polymorphisms of TGF-β1 has been studied in various inflammatory diseases. Our aim is to study the correlation of TGF-β1 gene polymorphism at codon 10 and 25 with the expression of serum level of TGF-β1 in a sample of Iraqi psoriatic patients compared to the control group.

MATERIALS AND METHODS

A cross-sectional study involved 100 patients with psoriasis vulgaris and 50 sex- and age-matched healthy volunteers as control group. Serum and genomic DNA were prepared from peripheral blood samples. Amplification refractory mutation system-polymerase chain reaction technique (ARMS-PCR) had been applied for genotyping TGF-β1 codon 10 [rs1982073] and codon 25 [rs1800471] genetic polymorphisms. Enzyme-linked immunosorbent assay technique (ELISA) based on the sandwich principle was used for quantification of serum TGF-β1 level. Psoriasis Area and Severity Index (PASI) scoring was applied for determining the severity in psoriatic patients and classified accordingly to mild (PASI<7), moderate (PASI 7-12), severe (PASI>12) groups.

RESULTS

Statistically significant difference was found in TGF-β1 gene polymorphism between psoriatic patients and control group at codon 10 (T869C) polymorphism (p=0.021) and codon 25 (G915C) polymorphism (p=0.040). No significant association was detected with the mean serum TGF-β1 level, severity of the disease, disease onset, gender, history of psoriatic arthritis, and smoking in both codons. Significant lower mean serum TGF-β1 level was found among psoriatic group (192.17 ± 531.12 ng/L) compared with controls (565.89 ± 1372.30 ng/L) (p = 0.018). Relation of mean serum TGF-β1 level with the onset of the disease was statistically significant (p = 0.004), early-onset disease group was lower (105.92 ± 68.02 ng/L) compared with the late-onset disease group (450.92 ±1027.79 ng/L). The mean serum TGF-β1 level showed no significant differences with the severity of psoriasis, gender, history of psoriatic arthritis, and smoking.

CONCLUSION

Iraqi population showed a significant association between TGF-β1 gene polymorphism at codon 10 and 25 were with psoriasis susceptibility, and a significantly lower mean serum TGF-β1 level was detected in psoriatic patients.

IL6R is a target of miR-197 in human keratinocytes

Psoriasis is a chronic inflammatory disorder with cutaneous and systemic manifestations and substantial negative effects on patients' quality of life. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression that play a role in the pathogenesis of psoriasis. Previously studies, from others and by us, highlighted specific miRNAs that are dysregulated in psoriatic lesions. MicroRNA-197-3p (miR-197) expression is downregulated in psoriatic lesions compared to normal or uninvolved skin in patients with psoriasis. We have previously reported that miR-197 could modulate IL-22 and IL-17 signalling in psoriasis. Herein, we identify additional biochemical targets of miR-197 in psoriasis. We applied a transcriptome-wide biochemical approach, Protein argonaute-2 photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (Ago2 PAR-CLIP), to search for new targets of miR-197 in live keratinocytes, and validated its results using reporter assay and analysing by Western blot protein levels in cells overexpressing miR-197. Ago2 PAR-CLIP identified biochemical targets of miR-197, including the alpha subunit of the IL-6 receptor (IL6R). This work provides evidence that IL6R in bona-fide biochemical target of miR-197. IL6R is known to be up-regulated in psoriasis and even was considered as a possible therapeutic target. From the present data and our previous studies, it appears that miR-197 is a major regulator of the interaction between immune system cells and keratinocytes.

Galectin-8 Is Upregulated in Keratinocytes by IL-17A and Promotes Proliferation by Regulating Mitosis in Psoriasis

Psoriasis is a chronic inflammatory skin disease that develops under the influence of the IL-23/T helper 17 cell axis and is characterized by intense inflammation and prominent epidermal hyperplasia. In this study, we demonstrate that galectin-8, a β-galactoside‒binding lectin, is upregulated in the epidermis of human psoriatic skin lesions as well as in a mouse model of psoriasis induced by intradermal IL-23 injections and in IL-17A‒treated keratinocytes. We show that keratinocyte proliferation is less prominent in galectin-8‒knockout mice after intradermal IL-23 treatment than in wild-type mice. In addition, we show that galectin-8 levels in keratinocytes are positively correlated with the ability of the cells to proliferate and that transitioning from mitosis into G1 phase is delayed in galectin-8‒knockout HaCaT cells after cell-cycle synchronization and release. We demonstrate by immunofluorescence staining and immunoblotting the presence of galectin-8 within the mitotic apparatus. We reveal by coimmunoprecipitation and mass spectrometry analysis that α-tubulin interacts with galectin-8 during mitosis. Finally, we show that in the absence of galectin-8, pericentrin compactness is lessened and mitotic microtubule length is shortened, as demonstrated by immunofluorescence staining. We conclude that galectin-8 is upregulated in psoriasis and contributes to the hyperproliferation of keratinocytes by maintaining centrosome integrity during mitosis through interacting with α-tubulin.

Protective and pathogenic roles of resident memory T cells in human skin disorders

The human skin is populated by recirculating T cells and skin-sessile resident memory T cells (T_RM). Skin T_RM are constructed during immune responses against antigens that the host immune system encounters in the skin. T_RM persist in the same sites for a long time and play important protective roles in skin immune responses in collaboration with other skin-composing cells such as dendritic cells and keratinocytes. These T_RM with strong effector functions possibly also engender skin inflammatory disorders. Since human skin T cells, especially T_RM, are phenotypically distinct from T cells in the blood circulation, T cells residing in the skin should be directly investigated, without presuming from the activities of blood T cells, in order to understand the functional characteristics of skin T cells in skin disorders. This review summarizes the features of human skin T_RM and reviews the immunopathological involvement of T_RM in human skin disorders such as infectious disease, inflammatory skin disease, and malignant skin tumors.

The Tissue-Engineered Human Psoriatic Skin Substitute: A Valuable In Vitro Model to Identify Genes with Altered Expression in Lesional Psoriasis

Psoriasis is a chronic inflammatory skin disease for which no cure has emerged. Its complex etiology requires the development of an in vitro model representative of the pathology. In this study, we exploited gene profiling analyses on microarray in order to characterize and further optimize the production of a human psoriatic skin model representative of this in vivo skin disease. Various skin substitutes were produced by tissue-engineering using biopsies from normal, healthy donors, or from lesional or non-lesional skin samples from patients with psoriasis, and their gene expression profiles were examined by DNA microarray. We demonstrated that more than 3540 and 1088 genes (two-fold change) were deregulated between healthy/lesional and lesional/non-lesional psoriatic substitutes, respectively. Moreover, several genes related to lipid metabolism, such as PLA2G4E and PLA2G4C, were identified as repressed in the lesional substitutes. In conclusion, gene profiling analyses identified a list of deregulated candidate genes associated with various metabolic pathways that may contribute to the progression of psoriasis.

Interaction of MTHFR gene with smoking and alcohol use and haplotype combination susceptibility to psoriasis in Chinese population

To investigate the association of MTHFR gene polymorphism and additional gene-gene interaction with psoriasis risk. GMDR model was used to screen the best gene-smoking and gene-drinking interaction combinations. Logistic regression was performed to investigate association between two SNPs and psoriasis. For psoriasis patient-control haplotype analyses, the SHEsis online haplotype analysis software ( http://analysis.bio-x.cn ) was employed. We found that carriers of homozygous mutant of rs1801133 polymorphism and heterozygous of rs1801131 are associated with increased psoriasis risk than those with wild-type homozygotes, OR (95%CI) were 2.01 (1.48-2.79), and 2.08 (1.56-2.86), respectively. We also found a significant gene-environment interaction between C677T and alcohol drinking. In all samples, the haplotype 1298A-677C was observed most frequently in two groups, with 49.43 and 55.71% for the patients and controls, respectively. The results also indicated that the haplotype containing 1298C and 677T alleles were associated with a statistically increased psoriasis risk, OR (95%CI) = 1.73 (1.12-2.46), P = 0.0002. Our study found that rs1801133, rs1801131 within MTHFR gene, and interaction between C677T and alcohol drinking and haplotype containing the 1298C and 677T alleles were all associated with increased psoriasis risk.

Human Organ Culture: Updating the Approach to Bridge the Gap from In Vitro to In Vivo in Inflammation, Cancer, and Stem Cell Biology

Human studies, critical for developing new diagnostics and therapeutics, are limited by ethical and logistical issues, and preclinical animal studies are often poor predictors of human responses. Standard human cell cultures can address some of these concerns but the absence of the normal tissue microenvironment can alter cellular responses. Three-dimensional cultures that position cells on synthetic matrices, or organoid or organ-on-a-chip cultures, in which different cell spontaneously organize contacts with other cells and natural matrix only partly overcome this limitation. Here, we review how human organ cultures (HOCs) can more faithfully preserve in vivo tissue architecture and can better represent disease-associated changes. We will specifically describe how HOCs can be combined with both traditional and more modern morphological techniques to reveal how anatomic location can alter cellular responses at a molecular level and permit comparisons among different cells and different cell types within the same tissue. Examples are provided involving use of HOCs to study inflammation, cancer, and stem cell biology.

Effect of psoriasis activity and topical treatment on plasma epidermal growth factor (EGF) and its soluble receptor (sEGFR)

BACKGROUND

Pathogenesis of psoriasis involves epidermal growth factor (EGF) that participates in keratinocyte proliferation, angiogenesis and cell differentiation through binding to soluble epidermal growth factor receptor (sEGFR). It is synthesised by, among others, keratinocytes, especially within psoriatic skin.

OBJECTIVE

To evaluate EGF and sEGFR plasma concentrations during topical psoriatic treatment.

METHODS

Blood samples were collected from 51 patients with plaque psoriasis. EGF and sEGFR plasma concentrations were examined with immunoenzymatic method prior and 14 days after topical treatment. The outcomes were analyzed with respect to PASI.

RESULTS

Mean EGF concentration was higher in the plasma of psoriatic patients compared to the control group (p = .401) while mean sEGFR concentration was over twofold lower compared to the control group (p < .001). After the therapy, an insignificant decrease in EGF plasma concentration (p = .835) and a significant increase in sEGFR concentration (p = .017) compared to initial values were observed. The coefficient of EGF/sEGFR concentration calculated for each individual had similar values before and after the treatment (p = .009), both of which were significantly higher compared to control group (respectively p < .001, p < .008).

CONCLUSION

Epidermal growth factor and its soluble receptor may be a useful markers in monitoring clinical course of psoriasis and the effectiveness of therapy.

Repression of GPRC5A is associated with activated STAT3, which contributes to tumor progression of head and neck squamous cell carcinoma

Background

G protein–coupled receptor family C group 5 member A (GPRC5A), a retinoic acid-inducible gene, is a lung tumor suppressor. Previously, we showed that repression of GPRC5A expression was associated with pathologic differentiation grade of oral squamous cell carcinomas (OSCC) and overexpression of GPRC5A gene inhibited the malignant phenotype in OSCC cells, suggesting that GPRC5A also functions as a tumor suppressor in oral cancer. However, the molecular mechanisms underlying GPRC5A deficiency in head and neck squamous cell carcinoma (HNSCC) are still unclear.

Methods

In this study, we used Western blot analysis and immunohistochemical (IHC) staining to investigate the expression of GPRC5A in both HNSCC cell lines and clinical samples. GPRC5A stable transfectants and their parental HNSCC cells were characterized for their biological activities in anchorage-independent growth.

Results

IHC analysis showed that, GPRC5A expression was high in normal tissue, but gradually decreased in oral leukoplakia, a precancerous stage, and greatly suppressed in primary cancer. Repression of GPRC5A was correlated with activated STAT3, which associates with aggressive clinicopathological features in HNSCC patients. Moreover, overexpression of GPRC5A suppressed IL-6-induced-STAT3 activation and inhibited anchorage-independent growth in HNSCC cells.

Conclusions

Repressed GPRC5A associates with increased tumor grade and activated STAT3, which may be used as a prognostic marker for tumor progression of HNSCC.

Bazex Syndrome in Lung Squamous Cell Carcinoma: High Expression of Epidermal Growth Factor Receptor in Lesional Keratinocytes with Th2 Immune Shift

An 82-year-old Japanese man was referred for detailed examination of hyperkeratotic erythematous plaques on his palms and soles for 6 months. Two weeks before his first visit, he had undergone lung lobectomy for right lung squamous cell carcinoma (SCC). Laboratory findings showed elevations of eosinophil counts, serum IgE, thymus and activation-regulated chemokine, SCC antigen, and soluble interleukin-2 receptor levels. Histological results of a skin biopsy involving the left palm showed psoriasiform dermatitis. Before lung lobectomy, the hyperkeratotic erythematous plaques on the palms and soles and the erythemas on the trunk and extremities were difficult to treat with topical steroids. After lobectomy, the skin symptoms dramatically and rapidly subsided with topical steroids. Therefore, we diagnosed Bazex syndrome (BS), also known as acrokeratosis paraneoplastica, as a paraneoplastic cutaneous disease in lung SCC. The mild eosinophilia subsided and levels of SCC antigen, IgE, and soluble interleukin-2 receptor were reduced. BS is a paraneoplastic cutaneous disease characterized by acral psoriasiform lesions associated with an underlying neoplasm. In a previous report, a shift to the Th2 immune condition was found in patients with non-small cell lung cancer, as shown in our patient. Epidermal growth factor receptor (EGFR) is also known as tumor growth factor-α receptor; it is increased in psoriatic keratinocytes. In our case, EGFR expression increased in lesional keratinocytes 2 weeks after surgery and decreased 4 weeks after surgery. We speculate that a shift to Th2 immune reactions in lung SCC may be the pathogenesis of BS, whereby lesional keratinocytes highly express EGFR in parallel with disease activity.

Effect of psoriasis activity on epidermal growth factor (EGF) and the concentration of soluble EGF receptor in serum and plaque scales

BACKGROUND

Epidermal growth factor receptors (EGFRs) are overexpressed in psoriatic keratinocytes, and regulate cell growth, proliferation and differentiation through binding to epidermal growth factor (EGF). The role of EGF and EGFRs in the pathogenesis of psoriasis and the contribution of their measurement to psoriasis management are still unknown.

AIM

To evaluate serum concentrations of EGF, soluble (s)EGFRs and EGF content in psoriatic scales of patients with severe psoriasis, and to analyse their association with the clinical activity of the disease.

METHODS

Serum samples and plaque scales were collected from 51 patients with plaque-type psoriasis. Concentrations of EGF and sEGFR in serum and of EGF in scales were measured using enzyme immunoassay. Data were analysed with respect to baseline Psoriasis Area and Severity Index (PASI).

RESULTS

Mean serum EGF concentration in patients was higher than in controls (701 ± 72 vs. 586 ± 63 pg/mL), but the difference was not significant. Mean serum concentration of sEGFR was significantly lower than controls (40.8 ± 1.4 vs. 86.4 ± 11.3 ng/mL, P < 0.001). Serum levels of EGF showed a significant positive correlation and EGFR showed a significant negative correlation with PASI (P < 0.05). No correlation was seen between PASI and EGF content in scales or between EGF and sEGFR levels. Serum EGF concentrations reached the highest mean level (914 ± 138 pg/mL) in patients with PASI > 20, and this was significantly higher than the mean of 414 ± 82 pg/mL in the group with PASI < 10. Mean sEGFR serum concentrations remained significantly lower than those of controls, irrespective of disease severity.

CONCLUSIONS

Compared with controls, patients with psoriasis had increased EGF and decreased sEGFR levels in serum. EGF and sEGFR levels correlated with disease severity.

The translational revolution and use of biologics in patients with inflammatory skin diseases

Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases characterized by immune-mediated inflammation and abnormal keratinocyte differentiation. Although T-cell infiltration characterizes both diseases, T-cell polarization differs. Psoriasis is currently the best model for translational medicine because many targeted therapeutics have been developed and testing of targeted therapeutics has cemented psoriasis as IL-23/TH17 polarized. In patients with AD, although therapeutic development is approximately a decade behind that in patients with psoriasis, there is now active development and testing of targeted therapeutics against various immune axes (TH2, TH22, and IL-23/TH17). These clinical trials and subsequent molecular analyses using human samples will be able to clarify the relative roles of polar cytokines in patients with AD.

An epidemiological study on trigger factors and quality of life in psoriatic patients

Objective:

to evaluate the role of stress, tobacco, drugs, infections, allergies, heredity, alcohol, hormones and skin aggressions as trigger factors and the impact on quality of life in a sample of psoriasis patients.

Methods:

a transversal study performed in 90 patients affected by psoriasis between January and November 2012 at the “Nene Tereza” University Hospital, Tirane, Albania, based on two scored questionnaires.

Results:

more than 70 % of patients reported that stressful events caused a flare- up of their psoriasis (p< 0.05). More than 60% of males and 20% of females were smokers (p< 0.05). About 20% of our patients were taking one or more of the medications listed in the questionnaire (p> 0.05). About 20% of patients reported having had recurrent infections (p<0,05). About 80% of males patients consumed alcohol (p<0,05). More than 40% reported a relative with psoriasis. Statistical comparison of the group that reported skin aggressions with the group that did not revealed a significant difference (p<0,05). Only a few of them reported to have allergies (p>0,05). About 36% of females reported that hormonal changes (puberty and menopause) exacerbated their psoriasis (p<0,05). More than 40% of patients reported that psoriasis seriously affects their quality of life.

Conclusion:

stress, tobacco, infections, heredity, alcohol, hormonal changes and skin aggressions were confirmed as trigger factors for psoriasis in the present sample. Allergies and the investigated drugs seemed not to have any influence in flare-ups. We found that psoriasis had a serious impact in the quality of life in over of 40% of the patients interviewed.

Effects of magnesium deficiency--more than skin deep

Dead Sea and magnesium salt therapy are two of the oldest forms of treatment for skin disease and several other disorders, supported by a body of largely anecdotal evidence. In this paper we review possible pathways for penetration of magnesium ions through the epidermis to reach the circulation, in turn replenishing cellular magnesium levels. We also discuss mechanisms for intercellular movement of magnesium ions and possible mechanisms for the interaction between magnesium ions and inflammatory mediators. Upon addition of magnesium ions in vitro, the expression of inflammatory mediators such as tumour necrosis factor α (TNFα) and nuclear factor κβ (NFκβ) is down regulated. Dysregulation of these and other inflammatory mediators has been linked to several inflammatory disorders, including asthma, arthritis, atherosclerosis and neuroinflammation.

Discovering aptamers by cell-SELEX against human soluble growth factors ectopically expressed on yeast cell surface

SELEX, the process of selecting aptamers, is often hampered by the difficulty of preparing target molecules in their native forms and by a lack of a simple yet quantitative assay for monitoring enrichment and affinity of reactive aptamers. In this study, we sought to discover DNA aptamers against human serum markers for potential therapeutic and diagnostic applications. To circumvent soluble expression and immobilization for performing SELEX, we ectopically expressed soluble growth factors on the surface of yeast cells to enable cell-SELEX and devised a flow cytometry-based method to quantitatively monitor progressive enrichment of specific aptamers. High-throughput sequencing of selected pools revealed that the emergence of highly enriched sequences concurred with the increase in the percentage of reactive aptamers shown by flow cytometry. Particularly, selected DNA aptamers against VEGF were specific and of high affinity (K(D)  = ∼ 1 nM) and demonstrated a potent inhibition of capillary tube formation of endothelial cells, comparable to the effect of a clinically approved anti-VEGF antibody drug, bevacizumab. Considering the fact that many mammalian secretory proteins have been functionally expressed in yeast, the strategy of implementing cell-SELEX and quantitative binding assay can be extended to discover aptamers against a broad array of soluble antigens.

Expression of CXCL1 in human endothelial cells induces angiogenesis through the CXCR2 receptor and the ERK1/2 and EGF pathways

Endothelial cell growth and proliferation are critical for angiogenesis; thus, greater insight into the regulation of pathological angiogenesis is greatly needed. Previous studies have reported on chemokine (C-X-C motif) ligand 1 (CXCL1) expression in epithelial cells and that secretion of CXCL1 from these epithelial cells induces angiogenesis. However, limited reports have demonstrated CXCL1 expression in endothelial cells. In this report, we present data that expand on the role of CXCL1 in human endothelial cells inducing angiogenesis. Specifically, CXCL1 is expressed and secreted from human endothelial cells. Interference of CXCL1 function using neutralizing antibodies resulted in a reduction in endothelial cell migration and viability/proliferation, the latter associated with a decrease in levels of cyclin D and cdk4. In vitro studies revealed that CXCL1 influenced neoangiogenesis through the regulation of epidermal growth factor and ERK1/2. In a xenograft angiogenesis model, interference of CXCL1 function resulted in inhibition of angiogenesis. A better understanding of the role of CXCL1 in the interactions between the endothelial and epithelial components will provide insight into how human tissues use CXCL1 to survive and thrive in a hostile environment.

hMena: altered expression in psoriatic skin

Psoriasis is a chronic inflammatory skin disease, characterized by an enhanced proliferation and a deregulated differentiation of keratinocytes. hMena is an actin regulatory protein involved in the control of cell motility and adhesion. hMena results up-modulated in several human tumors with respect to normal tissues and its expression has been positively correlated to proliferation rate, tumor size and aggressiveness in response to mitogenic stimuli, such as epidermal growth factor. The hyperproliferation of keratinocytes observed in psoriasis prompted us to evaluate hMena expression on biopsies collected from involved and uninvolved skin of 12 patients with active plaque-type psoriasis with respect to healthy skin. We analyzed the expression of hMena at transcript and protein levels by quantitative RT-PCR and immunohistochemistry. We correlated the expression of hMena to Ki67 proliferation index and to keratin 10 (K10) and keratin 16 (K16) used as markers of keratinocyte differentiation and activation. We demonstrated the expression of hMena in a hyperproliferative skin condition not related to neoplastic transformation. Interestingly, we observed that hMena is not expressed in healthy skin, but it becomes detectable in non-lesional areas and it is even more expressed in lesional psoriatic skin. In addition, we found that hMena expression is correlated to the rate of keratinocyte proliferation and activation. Hence, our observations indicate hMena as a new possible player, involved in the development and/or maintenance of the hyperproliferative state of psoriatic keratinocytes.

Indirubin-3'-(2,3 dihydroxypropyl)-oximether (E804) is a potent modulator of LPS-stimulated macrophage functions

Indirubin is a deep-red bis-indole isomer of indigo blue, both of which are biologically active ingredients in Danggui Longhui Wan, an ancient Chinese herbal tea mixture used to treat neoplasia and chronic inflammation and to enhance detoxification of xenobiotics. Multiple indirubin derivatives have been synthesized and shown to inhibit cyclin-dependent kinases (CDKs) and glycogen-synthase kinase (GSK-3β) with varying degrees of potency. Several indirubins are also aryl hydrocarbon receptor (AhR) agonists, with AhR-associated activities covering a wide range of potencies, depending on molecular structure. This study examined the effects of indirubin-3'-(2,3 dihydroxypropyl)-oximether (E804), a novel indirubin with potent STAT3 inhibitory properties, on basal and LPS-inducible activities in murine RAW264.7 macrophages. Using a focused commercial qRT-PCR array platform (SuperArray®), the effects of E804 on expression of a suite of genes associated with stress and toxicity were determined. Most genes up-regulated by LPS treatment were suppressed by E804; including LPS-induced expression of pro-inflammatory cytokines and receptors, apoptosis control genes, and oxidative stress response genes. Using qRT-PCR as a follow up to the commercial arrays, E804 treatment suppressed LPS-induced COX-2, iNOS, IL-6 and IL-10 gene expression, though the effects on iNOS and COX-2 protein expression were less dramatic. E804 also inhibited LPS-induced secretion of IL-6 and IL-10. Functional endpoints, including iNOS and lysozyme enzymatic activity, phagocytosis of fluorescent latex beads, and intracellular killing of bacteria, were also examined, and in each experimental condition E804 suppressed activities. Collectively, these results indicate that E804 is a potent modulator of pro-inflammatory profiles in LPS-treated macrophages.

Regulation generation: the suppressive functions of human regulatory T cells

Proper regulation of immune homeostasis is necessary to limit inflammation and prevent autoimmune and chronic inflammatory diseases. Many autoimmune diseases, such as psoriasis, are driven by vicious cycles of activated T cells that are unable to be suppressed by regulatory T cells. Effective suppression of auto-reactive T cells by regulatory T cells (Treg) is critical for the prevention of spontaneous autoimmune disease. Psoriatic Treg cells have been observed to a defect in their capacity to regulate, which clearly contributes to psoriasis pathogenesis. A challenge for translational research is the development of novel therapeutic interventions for autoimmune diseases that will result in durable remissions. Understanding the mechanism(s) of dysregulated T cell responses in autoimmune disease will allow for the development of future therapeutic strategies that may be employed to specifically target pathogenic, proinflammatory cells. Several reports have demonstrated a pathogenic role for Thl and Thl7 cells in psoriasis as well as other autoimmune diseases. Similarly, several laboratories have independently demonstrated functional defects in regulatory T cells isolated from patients with numerous divergent autoimmune diseases. One primary challenge of research in autoimmune diseases is therefore to restore the balance between chronic T cell activation and impairment of Treg suppressor mechanisms. To this end, it is critical to develop an understanding of the many suppressive mechanisms employed by Treg cells in hopes of developing more targeted therapeutic strategies for Treg-mediated autoimmune diseases.

Apurinic/apyrimidinic endonuclease 1 is a key modulator of keratinocyte inflammatory responses

Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1) functions in both DNA repair and redox signaling, making it an attractive emerging therapeutic target. However, the role of APE1 in cutaneous inflammatory responses is largely unknown. In this study, we report that APE1 is a key upstream regulator in TLR2-dependent keratinocyte inflammatory responses. We found that nuclear expression of APE1 in epidermal layers was markedly up-regulated in psoriatic skin. APE1 was essential for the transcriptional activation and nuclear translocation of hypoxia-inducible factor-1alpha and NF-kappaB, both of which are crucial for inflammatory signaling in keratinocytes. Moreover, APE1 played a crucial role in the expression of TLR2-mediated inflammatory mediators, including TNF-alpha, CXCL8, and LL-37, in HaCaT cells and human primary keratinocytes. Silencing of APE1 attenuated cyclin D1/cyclin-dependent kinase 4 expression and phosphorylation of ERK1/2 and Akt, thereby affecting keratinocyte proliferation. Importantly, TLR2-induced generation of reactive oxygen species contributed to the nuclear translocation and expression of APE1, suggesting an autoregulatory circuit in which the subcellular localization of APE1 is associated with the production of APE1 per se through reactive oxygen species-dependent signaling. Taken together, these findings establish a role for APE1 as a master regulator of TLR2-dependent inflammatory responses in human keratinocytes.

Serum and tissue expression of transforming growth factor beta 1 in psoriasis

BACKGROUND

In psoriasis, keratinocyte hyperplasia may be explained by imbalance of growth factors responsible for epidermal proliferation and altered metabolism of their receptors. Transforming growth factor-beta 1 (TGF-beta1) implications in the pathogenesis of psoriasis can be attributed to several mechanisms besides keratinocyte cell cycle inhibition.

OBJECTIVES

To evaluate the relation between serum and tissue levels of TGF-beta1 in psoriasis and their correlation with disease parameters.

PATIENTS AND METHODS

Serum and punch biopsy of involved and non-involved skin of 22 patients with psoriasis vulgaris and 10 controls were collected for quantification of TGF-beta1 by enzyme-linked immunosorbent assay kit.

RESULTS

Serum level of TGF-beta1 in psoriatic patients was higher than controls in a statistically non-significant manner. Correlations between serum level of TGF-beta1 and extent of the disease (P = 0.007) and Psoriasis Area and Severity Index (PASI) score (P = 0.005) were observed. Mean tissue levels of TGF-beta1 were highest in psoriatic lesions in contrast to normal skin of psoriatic patients and healthy controls, but not statistically significant. Correlation between tissue levels of TGF-beta1 in non-involved skin and extent of the disease (P = 0.007) and PASI score (P = 0.013) was detected. Correlation was detected between levels of TGF-beta1 in psoriatic plaques and serum of patients (P = 0.035), but not between levels of TGF-beta1 in non-involved skin and serum.

CONCLUSIONS

Tissue expression of TGF-beta1 in psoriasis may be affected by the stage of development of the lesion. The direct relation between TGF-beta1 in psoriatic plaques and serum imply that the mechanisms for TGF-beta1 production and release in both these compartments may be related.

Identification of glucocorticoid-induced TNF receptor-related protein ligand on keratinocytes: ligation by GITR induces keratinocyte chemokine production and augments T-cell proliferation

Glucocorticoid-induced tumor necrosis factor (TNF) receptor-related protein ligand (GITRL) is a recently described co-stimulatory molecule expressed by antigen-presenting cells (APCs). Activated keratinocytes are known to engage intraepithelial T cells through co-stimulatory molecules. This study investigated the expression and function of GITRL in resting keratinocytes. We showed by immunofluorescence and flow cytometry that keratinocytes from Balb/C and C57Bl/6 mice, as well as PAM 212 murine cell line keratinocytes and human epidermal keratinocytes (HEK), express cell-surface GITRL. Stimulation of murine skin biopsies and HEK with GITR fusion protein (GITR: Fc FP) resulted in mRNA induction for chemoattractants: cutaneous T-cell-attracting chemokine (CTACK), thymus and activation-regulated chemokine (TARC), IL-8, monocyte chemoattractant protein-1 (MCP-1), and murine beta-defensin 3 (MBD3). Immunofluorescent studies on mouse biopsies treated with GITR: Fc FP confirmed corresponding TARC and MCP-1 protein production by keratinocytes. Chemokine induction was shown to be NF-kappaB-mediated. T-cell proliferation was enhanced by the addition of keratinocytes. This was reversed by pretreatment with an anti-GITRL antibody. We conclude that keratinocytes express GITRL, and that through this important co-stimulatory molecule, they have the potential to influence T-cell numbers in the skin through chemokine production and through a direct cell-cell effect on T-cell proliferation.

Regulation of cell proliferation and migration by TAK1 via transcriptional control of von Hippel-Lindau tumor suppressor

Skin maintenance and healing after wounding requires complex epithelial-mesenchymal interactions purportedly mediated by growth factors and cytokines. We show here that, for wound healing, transforming growth factor-beta-activated kinase 1 (TAK1) in keratinocytes activates von Hippel-Lindau tumor suppressor expression, which in turn represses the expression of platelet-derived growth factor-B (PDGF-B), integrin beta1, and integrin beta5 via inhibition of the Sp1-mediated signaling pathway in the keratinocytes. The reduced production of PDGF-B leads to a paracrine-decreased expression of hepatocyte growth factor in the underlying fibroblasts. This TAK1 regulation of the double paracrine PDGF/hepatocyte growth factor signaling can regulate keratinocyte cell proliferation and is required for proper wound healing. Strikingly, TAK1 deficiency enhances cell migration. TAK1-deficient keratinocytes displayed lamellipodia formation with distinct microspike protrusion, associated with an elevated expression of integrins beta1 and beta5 and sustained activation of cdc42, Rac1, and RhoA. Our findings provide evidence for a novel homeostatic control of keratinocyte proliferation and migration mediated via TAK1 regulation of von Hippel-Lindau tumor suppressor. Dysfunctional regulation of TAK1 may contribute to the pathology of non-healing chronic inflammatory wounds and psoriasis.

Inflammatory signaling and aryl hydrocarbon receptor mediate synergistic induction of interleukin 6 in MCF-7 cells

The pleiotropic cytokine interleukin 6 (IL-6) is involved in immune cell homeostasis. Additionally, IL-6 expression and signaling in tumor cells have been shown to elicit both protumor and antitumor properties. There is a plethora of mechanistic knowledge regarding how IL-6 signal transduction translates to biological responses. However, there is little understanding as to what factors control IL-6 expression within a tumor cell environment. The studies presented herein show that, in MCF-7 breast and ECC-1 endocervical cancer cells, the stimulation of aryl hydrocarbon receptor (AHR) activity, in combination with IL-1beta or phorbol 12-myristate 13-acetate (PMA) treatment, results in a marked synergistic induction of IL-6 levels over what is seen without AHR activation. Chromatin immunoprecipitation experiments suggest that the regulation of IL-6 mRNA expression occurs at the chromatin level, as AHR presence on the IL-6 promoter was observed in response to treatment with AHR ligand. Synergistic induction of IL-6 expression was sustained for 72 hours, with accumulation of IL-6 protein reaching levels 4.8-fold above IL-1beta treatment alone. In addition, transcriptional regulation of the prototypic AHR responsive gene Cyp1a1 was negatively regulated by PMA and IL-1beta treatment. Silencing of RELA expression alleviated IL-1beta-mediated repression of AHR transcriptional activity, whereas PMA-mediated repression was maintained. Additionally, small interfering RNA studies reveal that AHR and RELA are necessary for synergistic induction of IL-6. The findings presented here reveal the AHR as a potential therapeutic target for selective modulation of IL-6 expression in some tumor cell types. The data also suggest a possible previously unrecognized mechanism of AHR-mediated tumor promotion.

Update on the natural history and systemic treatment of psoriasis

The onset of psoriatic disease and its associated comorbidities involves the interplay among a myriad of genetic and environmental risk factors. As we gain further insight into the immunopathogenesis of psoriasis, we hope it will provide the basis for the development of safer, more efficacious, and more durable therapeutics in the future. Given its enormous toll on patient health and quality of life, steps should be taken to prevent or decrease the risk for psoriasis-associated comorbidities through behavior modification and use of preventative health screenings and treatments. Future studies will need to be performed to determine if successful treatment of psoriasis will lead to a decreased risk for developing psoriasis-associated comorbidities over time.

Analysis of perforin expression in peripheral blood and lesions in severe and mild psoriasis

BACKGROUND

Perforin is a membrane-disrupting protein that allows the entry of granzymes into a target cell inducing degradation of target substances in the cytoplasm and nucleus thus leading to programmed cell death or apoptosis. Recent work demonstrated a possible involvement of perforin mediated cytotoxicity in immunopathogenesis of psoriasis.

OBJECTIVES

To investigate a difference in systemic (peripheral blood) and local (lesions) expression and distribution of perforin in psoriatic patients with severe and mild disease.

METHODS

Flow cytometry was used for simultaneous detection of intracellular (perforin) and cell surface antigens in peripheral blood lymphocytes. The expression of perforin in skin lesions was evaluated by immunohistochemistry.

RESULTS

Significant increase of perforin expression in T lymphocytes, especially cytotoxic CD8+ cells was found in severe psoriasis compared to mild disease (p<0.01 and p<0.05, respectively). There was also an increase of CD56+P+ NK cells (p<0.05) in severe compared to mild psoriasis. The psoriatic plaque of both, severe and mild disease were abundant with perforin showing no significant difference on local level.

CONCLUSION

Based on our results we suggest the association between perforin expression and disease severity.

Srcasm overexpression in psoriasis-insights into pathogenesis

BACKGROUND

Psoriasis is a prevalent, chronic cutaneous disorder associated with a T-cell lymphocytic infiltrate and altered keratinocyte growth. Some of the molecular features of enhanced keratinocyte growth include increased growth factor receptor activation leading to enhanced cellular tyrosine kinase activity. Receptor tyrosine kinases, including the epidermal growth factor (EGF) receptor, are important regulators of keratinocyte growth, and increased activity of this receptor has been detected in psoriasis. A recently discovered, novel regulator of Src tyrosine kinases, termed Src-activating and signaling molecule (Srcasm), has been shown to modulate EGF signaling and promote differentiation in human keratinocytes. Given the properties of Srcasm, it would be of interest to characterize its expression in psoriasis. In this study, the levels of Srcasm mRNA and protein are characterized, and the relationship of these experimental observations to the psoriasis pathogenesis is discussed.

METHODS

The levels of Srcasm mRNA were determined by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) on RNA isolated from unremarkable and lesional patient tissue. These data were supplemented by performing radioactive in situ hybridization on formalin-fixed biopsy specimens of psoriatic lesions and unremarkable epidermis. Expression of Srcasm protein was evaluated by protein immunohistochemistry and Western blotting of protein lysates derived from patient samples.

RESULTS

All experimental modalities show that levels of Srcasm mRNA and protein were elevated in psoriatic lesions compared to unremarkable epidermis.

CONCLUSIONS

Increased levels of Srcasm mRNA and protein are seen in psoriasis. Given what is known regarding Srcasm function, increased levels of this molecule in keratinocytes may represent a cell compensatory mechanism that is primed to re-establish a physiologic differentiation program.

Molecular cross-talk between the NFkappaB and STAT3 signaling pathways in head and neck squamous cell carcinoma

The development of head and neck squamous cell carcinoma (HNSCC) involves the accumulation of genetic and epigenetic alterations in tumor-suppressor proteins, together with the persistent activation of growth-promoting signaling pathways. The activation of epidermal growth factor receptor (EGFR) is a frequent event in HNSCC. However, EGFR-independent mechanisms also contribute to the activation of key intracellular signaling routes, including signal transducer and activator of transcription-3 (STAT3), nuclear factor kappaB (NFkappaB), and Akt. Indeed, the autocrine activation of the gp130 cytokine receptor in HNSCC cells by tumor-released cytokines, such as IL-6, can result in the EGFR-independent activation of STAT3. In this study, we explored the nature of the molecular mechanism underlying enhanced IL-6 secretion in HNSCC cells. We found that HNSCC cells display an increased activity of the IL-6 promoter, which is dependent on the presence of an intact NFkappaB site. Furthermore, NFkappaB inhibition downregulated IL-6 gene and protein expression, and decreased the release of multiple cytokines. Interestingly, interfering with NFkappaB function also prevented the autocrine/paracrine activation of STAT3 in HNSCC cells. These findings demonstrate a cross-talk between the NFkappaB and the STAT3 signaling systems, and support the emerging notion that HNSCC results from the aberrant activity of a signaling network.

Srcasm corrects Fyn-induced epidermal hyperplasia by kinase down-regulation

Src family tyrosine kinases (SFKs) are important regulators of epithelial cell growth and differentiation. Characterization of cellular mechanisms that regulate SFK activity will provide insights into the pathogenesis of diseases associated with increased SFK activity. Keratin 14-Fyn (K14) transgenic mice were derived to characterize the effect of Fyn on epidermal growth and differentiation in vivo. The epidermis of K14-Fyn mice is thickened, manifests prominent scale, and exhibits features consistent with hyperproliferation. Increased epidermal Fyn levels correlate with activation of p44/42 MAP kinases, STAT-3, and PDK-1, key signaling molecules that promote epithelial cell growth. The Src-activating and signaling molecule (Srcasm) is a substrate of SFKs that becomes tyrosine-phosphorylated downstream of the EGF receptor. In vitro, increased Srcasm levels promote activation of endogenous Fyn and keratinocyte differentiation. To study the in vivo effect of Srcasm upon Fyn, double transgenic lines were derived. K14-Fyn/Srcasm transgenic mice did not manifest the hyperproliferative phenotype. In contrast, K14-Fyn/Srcasm-P transgenic mice, which express a nonphosphorylatable Srcasm mutant, maintained the hyperproliferative phenotype. Resolution of the hyperproliferative phenotype correlated with reduced Fyn levels in vivo in three experimental systems: transgenic mice, primary keratinocytes, and cell lines. Biochemical studies revealed that Srcasm-dependent Fyn down-regulation requires Fyn kinase activity, phosphorylation of Srcasm, and the Srcasm GAT domain. Therefore, Srcasm is a novel regulator of Fyn promoting kinase down-regulation in a phosphorylation-dependent manner. Srcasm may act as a molecular "rheostat" for activated SFKs, and cellular levels of Srcasm may be important for regulating epithelial hyperproliferation associated with increased SFK activity.

Mitogen- and Stress-Activated Protein Kinase 1 Is Activated in Lesional Psoriatic Epidermis and Regulates the Expression of Pro-Inflammatory Cytokines

Mitogen- and stress-activated protein kinase 1 (MSK1) is a downstream target of both the p38 and extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinases (MAPKs). MSK1 stimulates transcription of different pro-inflammatory genes through activation of transcription factors. The purpose of this study was to investigate the expression and activation of MSK1 in lesional psoriatic skin and its role in cytokine production in cultured normal human keratinocytes. Western blotting revealed a consistent and significant increase in phosphorylated (activated) MSK1(Ser376) in lesional psoriatic skin. Immunofluorescence staining revealed the phosphorylated MSK1(Thr581) to be localized in the basal layers of the epidermis in lesional psoriatic skin. No staining was found in non-lesional psoriatic skin. Cultured human keratinocytes incubated with anisomycin or IL-1beta resulted in the phosphorylation of the p38 MAPK and MSK1(Ser376). MSK1(Ser376) phosphorylation was inhibited by pre-incubation with the p38 inhibitor SB 202190. Transfection of the keratinocytes with specific MSK1 small interfering RNA resulted in 80% reduction of MSK1 expression and 51, 40, and 31% decrease in IL-6, IL-8, and tumor necrosis factor-alpha protein production, respectively. This study demonstrates for the first time the expression of MSK1 in epidermal keratinocytes and increased activation focally in psoriatic epidermis. As MSK1 regulates the production of pro-inflammatory cytokines, it may play a role in the pathogenesis of psoriasis.

Prolonged MHC class II expression and CIITA transcription in human keratinocytes

A transcriptional cofactor, the MHC class II transactivator (CIITA), is a master regulator of MHC class II gene expression. CIITA expression is restricted in MHC class II-positive cells and is regulated by 4 (human) or 3 (mouse) promoters. To clarify the usage of human CIITA promoters in keratinocytes, we analyzed CIITA mRNA levels in IFN-gamma-stimulated normal human keratinocytes (NHK) by real-time PCR using promoter-specific primers. When the amount of total CIITA mRNA in NHK was quantified at 6h after IFN-gamma-stimulation, the amount of CIITA mRNA detected in NHK did not differ from that seen in the B cell line Raji or the IFN-gamma-stimulated macrophage cell line THP-1. Quantitative real-time PCR using promoter-specific primers showed that type IV CIITA mRNA was strongly transcribed and that type III CIITA mRNA was weakly transcribed in stimulated NHK, while no transcripts from pI and pII were detected. Although type IV mRNA in THP-1 was transiently transcribed by IFN-gamma-stimulation, transcription of type IV in IFN-gamma-stimulated keratinocytes was prolonged. This difference subsequently caused significantly higher expression at 72 h of MHC class II on NHK, compared with THP-1. This is the first report to quantitatively analyze each type of CIITA transcript in NHK.

Effect of psoriasis activity on metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in plasma and lesional scales

The aim of this study was to evaluate the association between psoriasis severity and concentrations of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in plasma and scales from psoriatic lesions, measured with an enzyme immunoassay in 24 patients and analysed with respect to psoriasis area and severity index (PASI). The mean plasma concentrations of both proteins in psoriatic patients significantly exceeded the control values. The proteins were also detectable in scales. There was a significant correlation between plasma MMP-1 concentration and the disease duration. The PASI values showed significant positive correlation with plasma TIMP-1 and significant negative correlation with MMP-1 content in scales. The highest plasma MMP-1 concentration was observed in patients with mild forms whereas the highest plasma TIMP-1 concentrations were demonstrated in severe forms of psoriasis. Our results confirm the role of these proteins in pathogenesis of psoriasis. In severe forms, a decrease in both MMP-1 and TIMP-1 was observed in scales, suggesting their insufficient tissue expression, which can be a crucial element of psoriasis aggravation.

Efficacy of etanercept in an integrated multistudy database of patients with psoriasis

BACKGROUND

The tumor necrosis factor (TNF) inhibitor etanercept has been demonstrated to be safe and effective for treating chronic plaque psoriasis in 3 clinical trials.

OBJECTIVES

To refine efficacy results for etanercept on the basis of a larger population size through the integration of the 3 studies, and to determine if the efficacy profile across all 3 studies is consistent with efficacy profiles observed for individual trials.

METHODS

In these integrated analyses, data for 1187 patients from 3 blinded treatment groups were pooled to compare efficacy at 12 weeks: etanercept 50 mg weekly (equivalent to 25 mg twice weekly) subcutaneously, etanercept 50 mg twice weekly subcutaneously, and placebo. The primary efficacy end point in all 3 studies was at least a 75% improvement in the Psoriasis Area and Severity Index (PASI 75). Other measurements included PASI 50, PASI 90, patient's and dermatologist's global assessments, and Dermatology Life Quality Index.

RESULTS

In the integrated analyses, statistically significant, dose-dependent improvements in PASI 75 at 12 weeks were observed in patients treated with etanercept 50 mg weekly (33%) and 50 mg twice weekly (49%), compared with the placebo group (3%; P < .05). Significant improvements also were seen in all secondary end points (PASI 50 and PASI 90 responses, patient's and dermatologist's global assessments, and Dermatology Life Quality Index) at 12 weeks. Subgroup analyses of baseline patient characteristics demonstrated that there were no statistically significant treatment-by-covariate interactions.

LIMITATIONS

A limitation of these integrated analyses is the relatively short (12-week) time frame.

CONCLUSION

The efficacy profile of etanercept in patients with psoriasis was consistent across multiple studies as shown in the integrated analyses of the primary and secondary end points. Etanercept demonstrated rapid, dose-dependent improvements in disease severity and quality of life consistently over all studies.

Cytokine and Anti-Cytokine Therapies for Psoriasis and Atopic Dermatitis

Since the discovery of cytokines as key mediators in inflammation, targeting the cytokine network has represented a promising therapeutic approach. Psoriasis and atopic dermatitis, as T cell-mediated diseases with a strong cytokine component and a high unmet medical need, have moved into the focus of experimental therapies. Whereas pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha are overexpressed in both diseases, a type 1 cytokine pattern predominates in psoriasis and a type 2 cytokine pattern is of pathophysiological importance at least in the initial stages of atopic dermatitis. Strategies for intervention into the cytokine network have included antagonism of pro-inflammatory cytokines (e.g. TNFalpha, interleukin [IL]-1, IL-8, IL-12, IL-18, IL-23) with neutralizing antibodies and soluble receptors, application of recombinant cytokines (e.g. IL-4, IL-10, IL-11, interferon [IFN]-gamma) to shift the cytokine balance, and administration of small molecules to modulate cytokine expression or signaling. Results from the clinic have led to novel therapeutic options as well as a better understanding of the pathophysiology of inflammatory skin diseases. This review highlights the various therapeutic strategies, results from the clinic (that are in some cases preliminary), and insights that can be drawn from the more advanced clinical studies and the use of approved cytokine-directed therapies.

Effect of psoriasis treatment on plasma concentrations of metalloproteinase-1 and tissue inhibitor of metalloproteinases-1

AIM

The aim of this study was to evaluate the effect of psoriasis treatment on plasma concentrations of metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) with respect to disease severity.

METHODS

MMP-1 and TIMP-1 were measured using an enzyme immunoassay in plasma of 32 patients before and after topical treatment. Data were analysed with respect to baseline values of the Psoriasis Area and Severity Index (PASI).

RESULTS

Baseline plasma concentrations of both TIMP-1 and MMP-1 (1487 +/- 102 and 21.0 +/- 2.5 ng/mL, respectively) were significantly higher (P = 0.02 and 0.03, respectively) than normal. Both TIMP-1 and MMP-1 decreased significantly after completion of treatment to values similar to normal (1112 +/- 127 and 11.3 +/- 1.3 ng/mL, respectively). There was a significant positive correlation (r = 0.522) between baseline PASI and TIMP-1 values. Significant differences were observed between baseline TIMP-1 concentrations in groups with PASI < 15 and PASI > 20. Baseline values (1697 +/- 162 ng/mL) in patients with severe course of the disease (PASI > 20) were significantly elevated in comparison to normal values. Treatment caused a decrease in TIMP-1 plasma concentrations in all groups, but a significant difference was noted only in patients with pretreatment PASI > 20. Baseline MMP-1 concentrations exceeded significantly normal values only in patients with PASI < 15 (27.2 +/- 6.3 ng/mL) and 15-20 (18.4 +/- 1.4 ng/mL). Treatment caused a significant decrease in MMP-1-values in all groups to levels similar to normal.

CONCLUSIONS

Our results confirm the role of TIMP-1 and MMP-1 in the pathogenesis of psoriasis. Pretreatment plasma TIMP-1 increased whereas MMP-1 decreased in patients with a more severe course of the disease. However, successful treatment causes normalization of these plasma protein concentrations irrespective of psoriasis baseline activity.

In vitro reproduction of clinical hallmarks of eczematous dermatitis in organotypic skin models

Dermatitis is a group of highly pruritic chronic inflammatory skin diseases which represents a major public-health problem worldwide. The prevalence of dermatitis has increased in recent years affecting up to 20% of the general population. Acute skin lesions are characterized by extensive degrees of intercellular edema of the epidermis (spongiosis) and a marked perivenular inflammatory cell infiltrate in the dermis. Keratinocytes within eczematous lesions exhibit a modified expression of proinflammatory cytokines, chemokines and cell-surface molecules. The pathophysiological puzzle of dermatitis is far from being elucidated completely, but skin infiltration of activated memory/effector T cells are thought to play the pivotal role in the pathogeneses. The aim of this study was the set-up of organotypic models mimicking the symptoms of eczematous dermatitis to provide a tool for therapeutic research in vitro. Therefore activated T cells (ATs) were integrated in organotypic skin and epidermis equivalents (SE, EE). These models enabled the reproduction of several clinical hallmarks of eczematous dermatitis: (1) T cells induce keratinocyte apoptosis, which leads to a reduced expression of the adhesion molecule E-cadherin (E-cad) and disruption of the epidermal barrier. (2) Expression of intercellular adhesion molecule-1 (ICAM-1) allows the attachment of leukocytes to epidermal cells. (3) Upregulation of neurotrophin-4 (NT-4) in the epidermis is thought to mediate pruritus in lesions by supporting nerve outgrowth. (4) Elevated levels of pro-inflammatory cytokines (IL-1alpha and IL-6) and chemokines (IL-8, IP-10, TARC, MCP-1, RANTES and eotaxin) amplify the inflammatory response and lead to an influx of secondary immunocells into the skin. The therapeutics dexamethasone and FK506 markedly reduce cytokines/chemokines production and epidermal damaging in these models. These data underline that activated memory/effector T cells induce eczematous changes in this HaCaT cell based organotypic skin equivalent. Furthermore it can be concluded that these models make it possible to investigate targets of therapeutics in skin.

IL-6, its receptors and its relationship with bcl-2 and bax proteins in infiltrating and in situ human breast carcinoma

AIMS

To characterize the expression pattern of IL-6 and its receptors (IL-6R(alpha) and gp130), to relate this pattern to bcl-2 and bax expression and to elucidate the effects on the proliferation/apoptosis equilibrium in benign conditions and in situ and infiltrating breast cancer.

METHODS AND RESULTS

The immunoexpression of IL-6 and its receptors (IL-6R(alpha) and gp130), and their relationship with bcl-2 and bax proteins, were studied in in situ and infiltrating tumours and in benign breast lesions by means of Western blotting and immunohistochemistry. The percentages of samples positive for IL-6, bcl-2 and bax and their immunoreaction densities were higher in in situ carcinomas and infiltrating tumours than in benign lesions; although in in situ lesions were not so high as in infiltrating tumours, except for bax, whose immunoexpression was as weak as in benign conditions, resulting in a bcl-2/bax ratio higher than in infiltrating tumours.

CONCLUSIONS

The high expression of IL-6 and its receptors in tumours might be related to the enhanced cell proliferation occurring in breast cancer. IL-6 could act by increasing bcl-2 expression and thus altering the proliferation/apoptosis balance toward neoplastic cell proliferation. The increased bax immunoreactivity observed only in infiltrating tumours, which was not so high as the increase in bcl-2 immunoreactivity, might be interpreted as an attempt to hinder cell proliferation.

Novel pharmacological approaches in the treatment of psoriasis

Progress in the understanding of psoriasis as a T-cell mediated inflammatory disease has led to the development of new immunomodulatory therapies. Currently the main focus is on the so-called biologics (or biological agents), including fusion proteins, monoclonal antibodies, cytokines and selective receptors. They mainly target single steps in the complex cascade of humoral and cellular inflammatory immuno-mechanisms that finally lead to the accelerated growth of epidermal and vascular cells in the psoriatic lesions. The most promising and advanced biological agents are discussed along with their influence on the critical pathophysiological steps in psoriasis, including depletion of T cells, blockade of initial T-cell activation and T-cell receptor (TCR) stimulation, blockade of costimulatory signals and T-cell proliferative signals as well as restoration of the T helper type 1 (Th1)/Th2 balance by diminishing type 1 cytokines and administration of type 2 cytokines. In addition to the biological agents, further development of 'classical' dermatological therapies, such as retinoids, or the discovery of new indications for non-dermatological agents contribute to the novel pharmacological approaches in the treatment of psoriasis.

Polymorphisms in the interleukin-20 gene: relationships to plaque-type psoriasis

We analyzed the frequency of single-nucleotide polymorphisms (SNPs) at positions -1053 (rs 2981572), 1380 (rs 2981573), 1462 (rs 2232360), and 3978 (rs 1518108) of the human interleukin-20 (IL-20) gene by tetraprimer ARMS-PCR method. A significant association between patients with psoriasis and the G allele at position -1053 (P<0.05) was established. The pairwise linkage disequilibrium (LD) matrix showed that the nearly complete LD was present within the polymorphisms at positions -1053, 1380, and 1462 of the IL-20 gene. We found that patients with plaque psoriasis had a higher frequency of the HT3 GAA haplotype (P<0.01, OR 2.341, 95% CI: 1.346-4.074) compared to the control group. Likewise, the HT3 GAA haplotype was associated with an increased risk of early-onset psoriasis (P<0.01, OR 2.305, 95% CI: 1.285-4.132), late onset of disease (P<0.01, OR 2.542, 95% CI: 1.266-5.102), familial psoriasis (P<0.02, OR 2.220, 95% CI: 1.249-3.945), and sporadic disease (P<0.01, OR 2.523, 95% CI: 1.390-4.580). Our data indicate that IL-20 gene polymorphisms should have a role in determining susceptibility to plaque-type psoriasis. The possible role of the studied SNPs in the regulation of the expression of IL-20 is unknown yet and needs further studies.

Current concepts in the immunopathogenesis of psoriasis

There is much evidence to support the concept that psoriasis is a type 1 autoimmune disease, primarily mediated by interferon gamma and other inflammatory cytokines. There has been renewed interest in the role of components of the innate immune system, however,and it may be that overlap between the innate and acquired arms of the immune system can better explain immunopathogenesis in psoriasis. Relevant cell types, receptors, and immune mediators within these traditional boundaries of the immune system are discussed.Finally, pathogenic contributions from important psoriatic mouse models and recent genomic data using the new gene chip technology are elaborated.

Normalized proliferation of normal and psoriatic keratinocytes by suppression of sAPPalpha-release

The soluble form of the beta-amyloid precursor protein (sAPPalpha) is known to function in the autocrine regulation of epidermal growth and repair. Here we show that its proteolytic release by alpha-secretase in normal human keratinocytes is susceptible to hydroxamic-acid-based zinc metalloproteinase inhibitors and suppressed by these inhibitors by 80%-90%. As various other growth factors participate in regulating epidermal growth we investigated whether the inhibitor-induced sAPPalpha-deficiency would affect keratinocyte proliferation. At optimal inhibitor concentrations the suppression of sAPPalpha-release was followed by a decline in proliferation by 50%-60%, indicating that sAPPalpha is a major growth factor that cannot be compensated for by other growth factors. This finding was the basis for the treatment of human lesional psoriatic keratinocytes with these inhibitors, which resulted in the normalization of their increased proliferation rates. The reversibility of these effects and the lack of toxicity underline the value of these inhibitors and suggest their therapeutic application in psoriatic skin diseases.

Possible role of Malassezia furfur in psoriasis: modulation of TGF-beta1, integrin, and HSP70 expression in human keratinocytes and in the skin of psoriasis-affected patients

BACKGROUND

Psoriasis is a disease characterized by an abnormal pattern of keratinocyte growth and differentiation. Malassezia furfur forms part of the normal human skin flora. It may also be involved in the pathogenesis of psoriasis. To define the role of M. furfur in the pathogenesis of psoriasis, we investigated how M. furfur regulates molecules involved in cell migration and proliferation. The experiments were performed using human keratinocytes and skin biopsies from M. furfur-positive and -negative psoriasis-affected patients. In addition, we examined the signal transduction mechanisms involved.

MATERIALS AND METHODS

Western blot analysis was performed on human keratinocytes lysates treated or untreated with M. furfur and on biopsies from healthy and psoriasis patients. Signal transduction mechanisms involved were evaluated by electrophoretic mobility shift assay using the AP-1 inhibitor curcumin.

RESULTS

We found that M. furfur up-regulates transforming growth factor-beta1 (TGF-beta1), integrin chain, and HSP70 expression in human keratinocytes via AP-1-dependent mechanism. In the biopsies of M. furfur-positive psoriasis-affected patients, an increase in TGF-beta1, integrin chains, and HSP70 expression was found.

CONCLUSION

Our data suggest that M. furfur can induce the overproduction of molecules involved in cell migration and hyperproliferation, thereby favoring the exacerbation of psoriasis.

Pulmonary alveolar proteinosis associated with psoriasis and complicated by mycobacterial infection: Successful treatment with granulocyte-macrophage colony stimulating factor after a partial response to whole lung lavage

Pulmonary alveolar proteinosis (PAP) is a rare lung disease. Although whole lung lavage is considered the most effective treatment, not every patient shows a complete response. The case ofa young man with PAP in association with psoriasis who underwent frequent whole lung lavage but only achieved remission following treatment with granulocyte-macrophage colony stimulating factor (GM-CSF) is reported. His lung problem was complicated by atypical mycobacterial infection,which resolved with treatment. The role of GM-CSF is discussed.

Psoriasis genomics: analysis of proinflammatory (type 1) gene expression in large plaque (Western) and small plaque (Asian) psoriasis vulgaris

BACKGROUND

Type 1 T cells are hypothesized to be central in the immunopathogenesis of psoriasis. Through elaboration of interferon (IFN)-gamma, type 1 T cells regulate the expression of many 'downstream' inflammatory genes, including an array of chemokines that regulate leucocyte trafficking and activation in skin lesions. Accordingly, disease progression and/or severity might be controlled by the degree to which differing cytokines and chemokines are overexpressed in focal skin regions. To examine this possibility, we studied two forms of chronic psoriasis vulgaris that differ significantly in overall severity and progression: small plaque (SP) psoriasis occurring in Korean patients, and large plaque (LP) psoriasis occurring in North American patients.

OBJECTIVES

To characterize LP and SP psoriasis vulgaris with respect to expression of proinflammatory genes that define the type 1 T-cell axis in skin lesions [genes encoding interleukin (IL)-12, IFN-gamma, and IFN-gamma-regulated chemokines or inflammatory mediators].

METHODS

Total cellular RNA of skin samples from groups of patients with LP or SP psoriasis was analysed by quantitative reverse transcription-polymerase chain reaction (TaqMan analysis) to compare the differences in mRNA expression of genes related to the IFN-gamma pathway.

RESULTS

The mRNA expression of keratin 16, CD25, IFN-gamma, IL-12 p40, signal transducer and activator of transcription-1, inducible nitric oxide synthase, IL-8, macrophage inflammatory protein-3alpha, monocyte chemoattractant protein-1, S100A12, IFN-gamma-inducible protein of 10 kDa, IFN-inducible T-cell alpha-chemoattractant and monokine induced by IFN-gamma was increased in the lesions of both LP psoriasis and SP psoriasis. However, IL-18 mRNA expression was significantly different in the lesions of LP psoriasis in comparison with those of SP psoriasis.

CONCLUSIONS

The results indicate that proinflammatory type 1 genes regulated by IFN-gamma are similarly increased in both SP and LP psoriasis, but a potential difference in IL-18 exists between these disease forms. The consistent activation of this set of genes argues for a central role of IFN-gamma as a molecular regulator of inflammation in these distinct subtypes of psoriasis vulgaris. In contrast, disease extent/severity must be controlled by yet other factors.