Large-Scale Imputation of KIR Copy Number and HLA Alleles in North American and European Psoriasis Case-Control Cohorts Reveals Association of Inhibitory KIR2DL2 With Psoriasis.

Killer cell immunoglobulin-like receptors (KIR) regulate immune responses in NK and CD8+ T cells via interaction with HLA ligands. KIR genes, including KIR2DS1, KIR3DL1, and KIR3DS1 have previously been implicated in psoriasis susceptibility. However, these previous studies were constrained to small sample sizes, in part due to the time and expense required for direct genotyping of KIR genes. Here, we implemented KIR*IMP to impute KIR copy number from single-nucleotide polymorphisms (SNPs) on chromosome 19 in the discovery cohort (n=11,912) from the PAGE consortium, University of California San Francisco, and the University of Dundee, and in a replication cohort (n=66,357) from Kaiser Permanente Northern California. Stratified multivariate logistic regression that accounted for patient ancestry and high-risk HLA alleles revealed that KIR2DL2 copy number was significantly associated with psoriasis in the discovery cohort (p ≤ 0.05). The KIR2DL2 copy number association was replicated in the Kaiser Permanente replication cohort. This is the first reported association of KIR2DL2 copy number with psoriasis and highlights the importance of KIR genetics in the pathogenesis of psoriasis.

Virus-Like Particle-Mediated Vaccination against Interleukin-13 May Harbour General Anti-Allergic Potential beyond Atopic Dermatitis.

Virus-like particle (VLP)-based anti-infective prophylactic vaccination has been established in clinical use. Although validated in proof-of-concept clinical trials in humans, no VLP-based therapeutic vaccination against self-proteins to modulate chronic disease has yet been licensed. The present review summarises recent scientific advances, identifying interleukin-13 as an excellent candidate to validate the concept of anti-cytokine vaccination. Based on numerous clinical studies, long-term elimination of IL-13 is not expected to trigger target-related serious adverse effects and is likely to be safer than combined targeting of IL-4/IL-13. Furthermore, recently published results from large-scale trials confirm that elimination of IL-13 is highly effective in atopic dermatitis, an exceedingly common condition, as well as eosinophilic esophagitis. The distinctly different mode of action of a polyclonal vaccine response is discussed in detail, suggesting that anti-IL-13 vaccination has the potential of outperforming monoclonal antibody-based approaches. Finally, recent data have identified a subset of follicular T helper cells dependent on IL-13 which selectively trigger massive IgE accumulation in response to anaphylactoid allergens. Thus, prophylactic IL-13 vaccination may have broad application in a number of allergic conditions.

Phototherapy achieves significant cost savings by the delay of drug-based treatment in psoriasis.

BACKGROUND: Although used for decades in psoriasis, access to phototherapy is becoming increasingly restricted. Besides patient inconvenience, this is in large part to do with a perception of "high cost." We previously reported a comprehensive analysis of direct and indirect phototherapy treatment cost. However, no robust data exist on the actual savings associated with providing phototherapy in the treatment pathway. OBJECTIVES: To quantify the cost savings achieved by phototherapy by delaying alternative treatments. METHODS: Costs accruing through the UK-wide established treatment pathway with and without phototherapy were analysed. Direct and indirectly incurred drug treatment costs were calculated using drug tariff, laboratory cost, estate rates and clinic review costs. To enhance reliability, ranges of cost scenarios were calculated by varying parameters such as drug dosing. RESULTS: Medium annual cost savings per patient were £2200 [range: £1800-£2900] for NB-UVB, and £3700 [range: £2500-£5300] if both NB-UVB and PUVA courses were administered, respectively. As the provider treated 656 ± 76 patients per year during the 6-year observational window, this amounted to savings of £Mio 2.4 [range: £Mio 1.6-£Mio 3.4], even excluding additional non-modelled drug-associated costs (eg diagnostics, adverse event management). Since we only consider cost savings by delay of drug treatment for the duration of phototherapy, drug price reductions through biosimilar introduction only have a small effect. We provide spreadsheets allowing adaptation cost savings projections by varying input variables. CONCLUSIONS: Healthcare providers may achieve significant cost savings by implementing and/or widening access to phototherapy.

Feasibility Analysis of Interleukin-13 as a Target for a Therapeutic Vaccine.

BACKGROUND: The development of therapeutic vaccines requires thorough knowledge of potential hazards associated with long-term inactivation of self-proteins. Among potential targets, interleukin 13 (IL-13) merits consideration, as monoclonal antibodies disrupting IL-13 signaling are proving to be exceedingly effective in common conditions such as atopic dermatitis. OBJECTIVE: Given the mass publication of scientific data, an appraisal of safety aspects is challenging. METHODS: We here provide a three-fold approach to survey clinically relevant information on off-target effects, both adverse and beneficial, that may potentially be encountered in patients undergoing long-term IL-13 inactivation. First, we review non-clinical data in vivo and in vitro. Second, we summarize safety data accumulating from patients dosed with anti-IL-13 drugs. Third, we exploit human mutation data as well as emerging large-scale genetic datasets (global exome data from 60,000 patients) to obtain information on any association of IL-13-inactivating genetic variants with disease states. In addition, we: (1) dissect the precise efficacy signals obtained with various drugs targeting IL-13 and/or IL-4, and (2) summarize unintended, but potentially beneficial effects of prolonged IL-13 inactivation on several functional systems. RESULTS: Prolonged repression of IL-13 in several thousand patients so far has not uncovered any non-redundant functions of IL-13 in immune defense. Furthermore, missense mutations in the key genes IL-13, IL-13Rα1, IL-13Rα2, IL-4, IL-4Rα are common, while no case reports have been published on any immune deficiency or increased risk of neoplastic disease associated with such mutations, suggesting that these genes do not harbor non-redundant roles in adult outbred humans. In terms of efficacy, data from clinically used drugs strongly suggest that targeting IL-13 only, as opposed to IL-13 and IL-4, may be effective in eczema while being more selective. Importantly, several lines of evidence suggest that inhibition of IL-13 may in fact harbor potentially beneficial effects on non-targeted systems, including glucose metabolism, hepatic fibrosis, and atherosclerosis, suggesting that respective outcomes should be systematically captured in patients dosed with IL-13 interfering drugs. Collectively, available evidence suggests that IL-13 may fulfill safety requirements required for the target of a therapeutic vaccine.

Candidate long-range regulatory sites acting on the IL17 pathway genes TRAF3IP2 and IL17RA are associated with psoriasis.

BACKGROUND: Drug-mediated disruption of IL17A, IL17F and IL17RA proteins is effective in psoriasis. However, disruption of the IL17 pathway by functional mutations has so far only been shown to affect risk in IL23R and TRAF3IP2. It is unclear whether this is due to rarity of disruptive mutations. OBJECTIVE: (a) To delineate the prevalence of mutations in key IL17 pathway genes and (b) to identify candidate regulatory sites acting on IL23R, IL17A, IL17RA and TRAF3IP2 from a distance. METHODS: Extraction of mutation frequencies from ExAc data, evolutionary sequence alignment; mapping of long-range interacting (LRI) enhancers; and genetic association testing in a novel psoriasis cohort. RESULTS: The prevalence of disruptive mutations in genes such as IL17RA is sufficient to have been detectable by existing data sets. Therefore, lack of their association with psoriasis indicates that genetic risk primarily resides in variants acting from a distance. We identify two LRI enhancer sites, regulating IL17RA and TRAF3IP2, respectively. The TRAF3IP2 regulator localizes to the TRAF3IP2 antisense promoter, suggesting feedback regulation. Both LRI sites are associated with psoriasis in a novel Scottish psoriasis cohort and the TRAF3IP2-LRI at rs71562294 replicates in the WTCCC cohort. CONCLUSION: Genetic risk for psoriasis may be encoded at LRI sites regulating IL17 pathway genes from a distance.

Incorporation of tetanus-epitope into virus-like particles achieves vaccine responses even in older recipients in models of psoriasis, Alzheimer's and cat allergy.

Monoclonal antibodies are widely used to treat non-infectious conditions but are costly. Vaccines could offer a cost-effective alternative but have been limited by sub-optimal T-cell stimulation and/or weak vaccine responses in recipients, for example, in elderly patients. We have previously shown that the repetitive structure of virus-like-particles (VLPs) can effectively bypass self-tolerance in therapeutic vaccines. Their efficacy could be increased even further by the incorporation of an epitope stimulating T cell help. However, the self-assembly and stability of VLPs from envelope monomer proteins is sensitive to geometry, rendering the incorporation of foreign epitopes difficult. We here show that it is possible to engineer VLPs derived from a non human-pathogenic plant virus to incorporate a powerful T-cell-stimulatory epitope derived from Tetanus toxoid. These VLPs (termed CMVTT) retain self-assembly as well as long-term stability. Since Th cell memory to Tetanus is near universal in humans, CMVTT-based vaccines can deliver robust antibody-responses even under limiting conditions. By way of proof of concept, we tested a range of such vaccines against chronic inflammatory conditions (model: psoriasis, antigen: interleukin-17), neurodegenerative (Alzheimer's, ß-amyloid), and allergic disease (cat allergy, Fel-d1), respectively. Vaccine responses were uniformly strong, selective, efficient in vivo, observed even in old mice, and employing low vaccine doses. In addition, randomly ascertained human blood cells were reactive to CMVTT-VLPs, confirming recognition of the incorporated Tetanus epitope. The CMVTT-VLP platform is adaptable to almost any antigen and its features and performance are ideally suited for the design of vaccines delivering enhanced responsiveness in aging populations.

Narrowband UVB treatment is highly effective and causes a strong reduction in the use of steroid and other creams in psoriasis patients in clinical practice.

BACKGROUND: Narrowband NB-UVB phototherapy (NB-UVB) is an effective treatment for psoriasis, as demonstrated by clinical trials. However, due to required infrastructure and need for treatment attendance opinions on the value of offering this treatment in routine practice vary. AIMS: To provide high quality large-scale and long-term data on the efficacy of NB-UVB for psoriasis under real-world conditions in order to assist in management decisions. METHODS: The following resources were employed: (1) complete and prospectively recorded prescription drug records for a population of 420,000 marked by low demographic mobility, (2) prospectively recorded clinical treatment outcomes for all NB-UVB treatment episodes occurring in the local population; (3) complete dermatology electronic treatment records of all psoriasis patients, allowing cross-validation of diagnoses and treatment records. Using these data sets, we analysed all first-ever initial NB-UVB treatment episodes occurring over 79 months (n = 1749) for both clinical outcomes and the effect of NB-UVB on the use of topical treatments for psoriasis. RESULTS: Around 75% of patients both achieved a status of "clear/minimal disease" and used fewer topical treatments. NB-UVB treatment led to a strong reduction for both steroid creams (25%) and psoriasis-specific topicals, e.g. vitamin-D products (30%) during the 12-month period following NB-UVB treatment. The effects measured were specific as no effect of NB-UVB was noted on drug prescriptions unrelated to psoriasis. Results were independent of individuals administering and/or scoring treatment, as they were highly similar between four geographically separate locations. CONCLUSIONS: NB-UVB treatment is highly effective and leads to a remarkable reduction in the need for topical cream treatments for a period of at least 12 months.

Safety and Efficacy of Methotrexate in Psoriasis: A Meta-Analysis of Published Trials.

BACKGROUND: Methotrexate (MTX) has been used to treat psoriasis for over half a century. Even so, clinical data characterising its efficacy and safety are sparse. OBJECTIVE: In order to enhance the available evidence, we conducted two meta-analyses, one for efficacy and one for safety outcomes, respectively, according to PRISMA checklist. (Data sources, study criteria, and study synthesis methods are detailed in Methods). RESULTS: In terms of efficacy, only eleven studies met criteria for study design and passed a Cochrane risk of bias analysis. Based on this limited dataset, 45.2% [95% confidence interval 34.1-60.0] of patients achieve PASI75 at primary endpoint (12 or 16 weeks, respectively, n = 705 patients across all studies), compared to a calculated PASI75 of 4.4 [3.5-5.6] for placebo, yielding a relative risk of 10.2 [95% C.I. 7.1-14.7]. For safety outcomes, we extended the meta-analysis to include studies employing the same dose range of MTX for other chronic inflammatory conditions, e.g. rheumatoid arthritis, in order not to maximise capture of relevant safety data. Based on 2763 patient safety years, adverse events (AEs) were found treatment limiting in 6.9 ± 1.4% (mean ± s.e.) of patients treated for six months, with an adverse effect profile largely in line with that encountered in clinical practice. Finally, in order to facilitate prospective clinical audit and to help generate long-term treatment outcomes under real world conditions, we also developed an easy to use documentation form to be completed by patients without requirement for additional staff time. LIMITATIONS: Meta-analyses for efficacy and safety, respectively, employed non-identical selection criteria. CONCLUSIONS: These meta-analyses summarise currently available evidence on MTX in psoriasis and should be of use to gauge whether local results broadly fall within outcomes.

Beyond passive immunization: toward a nanoparticle-based IL-17 vaccine as first in class of future immune treatments.

Nanoparticles occur naturally as part of repetitive molecular structures forming virus-like particles (VLPs). VLPs are powerful immune activators. Specifically, VLP can elicit a direct activation of B lymphocytes to trigger production of antibodies targeted at molecules chemically linked to the VLP. We here review recent data from genetics research, large-scale genomic sequencing, as well as clinical trials which suggest that a VLP-based vaccine against the signaling molecule IL-17 will be safe and effective in the common skin disease psoriasis, as well as other conditions. Active vaccination against IL-17 is capable of replacing the costly manufacture of antibodies currently in clinical use with huge implications for treatment availability and health economics.

Skin-targeted inhibition of PPAR ß/δ by selective antagonists to treat PPAR ß/δ-mediated psoriasis-like skin disease in vivo.

We have previously shown that peroxisome proliferator activating receptor ß/δ (PPAR ß/δ is overexpressed in psoriasis. PPAR ß/δ is not present in adult epidermis of mice. Targeted expression of PPAR ß/δ and activation by a selective synthetic agonist is sufficient to induce an inflammatory skin disease resembling psoriasis. Several signalling pathways dysregulated in psoriasis are replicated in this model, suggesting that PPAR ß/δ activation contributes to psoriasis pathogenesis. Thus, inhibition of PPAR ß/δ might harbour therapeutical potential. Since PPAR ß/δ has pleiotropic functions in metabolism, skin-targeted inhibition offer the potential of reducing systemic adverse effects. Here, we report that three selective PPAR ß/δ antagonists, GSK0660, compound 3 h, and GSK3787 can be formulated for topical application to the skin and that their skin concentration can be accurately quantified using ultra-high performance liquid chromatography (UPLC)/mass spectrometry. These antagonists show efficacy in our transgenic mouse model in reducing psoriasis-like changes triggered by activation of PPAR ß/δ. PPAR ß/δ antagonists GSK0660 and compound 3 do not exhibit systemic drug accumulation after prolonged application to the skin, nor do they induce inflammatory or irritant changes. Significantly, the irreversible PPAR ß/δ antagonist (GSK3787) retains efficacy when applied topically only three times per week which could be of practical clinical usefulness. Our data suggest that topical inhibition of PPAR ß/δ to treat psoriasis may warrant further exploration.

Wnt5a is strongly expressed at the leading edge in non-melanoma skin cancer, forming active gradients, while canonical Wnt signalling is repressed.

Wnt5a is one of the so-called non-canonical Wnt ligands which do not act through ß-catenin. In normal development, Wnt5a is secreted and directs the migration of target cells along concentration gradients. The effect of Wnt5a on target cells is regulated by many factors, including the expression level of inhibitors and receptors. Dysregulated Wnt5a signalling facilitates invasion of multiple tumor types into adjacent tissue. However, the expression and distribution of Wnt5a in cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), as well as the effect of Wnt5a on keratinocyte migration has not been studied in detail to date. We here report that Wnt5a is upregulated in SCC and BCC and localised to the leading edge of tumors, as well as tumor-associated fibroblasts. The Wnt5a-triggered bundling of its receptor Fzd3 provides evidence of Wnt5a concentration gradients projecting into the tumor. In vitro migration assays show that Wnt5a concentration gradients determine its effect on keratinoctye migration: While chemotactic migration is inhibited by Wnt5a present in homogenous concentrations, it is enhanced in the presence of a Wnt5a gradient. Expression profiling of the Wnt pathway shows that the upregulation of Wnt5a in SCC is coupled to repression of canonical Wnt signalling. This is confirmed by immunohistochemistry showing lack of nuclear ß-catenin, as well as absent accumulation of Axin2. Since both types of Wnt signalling act mutually antogonistically at multiple levels, the concurrent repression of canonical Wnt signalling suggests hyper-active Wnt5a signal transduction. Significantly, this combination of gene dysregulation is not observed in the benign hyperproliferative inflammatory skin disease psoriasis. Collectively, our data strongly suggest that Wnt5a signalling contributes to tissue invasion by non-melanoma skin cancer.

Protective effect of human endogenous retrovirus K dUTPase variants on psoriasis susceptibility.

Previous genetic and functional studies have implicated the human endogenous retrovirus K (HERV-K) dUTPase located within the PSORS1 locus in the major histocompatibility complex region as a candidate psoriasis gene. Here, we describe a variant discovery and case-control association study of HERV-K dUTPase variants in 708 psoriasis cases and 349 healthy controls. Five common HERV-K dUTPase variants were found to be highly associated with psoriasis, with the strongest association occurring at the missense single-nucleotide polymorphism (SNP) rs3134774 (K158R, P=3.28 × 10(-15), odds ratio =2.36 (95% confidence interval: 1.91-2.92)). After adjusting the association of the HERV-K dUTPase variants for the potential confounding effects of HLA alleles associated with psoriasis, the HERV-K SNPs rs9264082 and rs3134774 remained significantly associated. Haplotype analysis revealed that HERV-K haplotypes containing the non-risk alleles for rs3134774 and rs9264082 significantly reduced the risk of psoriasis. Functional testing showed higher antibody responses against recombinant HERV-K dUTPase in psoriasis patients compared with controls (P<0.05), as well as higher T-cell responses against a single HERV-K dUTPase peptide (P<0.05). Our data support an independent role for the HERV-K dUTPase on psoriasis susceptibility, and suggest the need for additional studies to clarify the role of this dUTPase in the pathogenesis of psoriasis.

Activation of PPARbeta/delta causes a psoriasis-like skin disease in vivo.

BACKGROUND: Psoriasis is one of the most frequent skin diseases world-wide. The disease impacts enormously on affected patients and poses a huge financial burden on health care providers. Several lines of evidence suggest that the nuclear hormone receptor peroxisome proliferator activator (PPAR) beta/delta, known to regulate epithelial differentiation and wound healing, contributes to psoriasis pathogenesis. It is unclear, however, whether activation of PPARbeta/delta is sufficient to trigger psoriasis-like changes in vivo. METHODOLOGY/PRINCIPAL FINDINGS: Using immunohistochemistry, we define the distribution of PPARbeta/delta in the skin lesions of psoriasis. By expression profiling, we confirm that PPARbeta/delta is overexpressed in the vast majority of psoriasis patients. We further establish a transgenic model allowing inducible activation of PPARbeta/delta in murine epidermis mimicking its distribution in psoriasis lesions. Upon activation of PPARbeta/delta, transgenic mice sustain an inflammatory skin disease strikingly similar to psoriasis, featuring hyperproliferation of keratinocytes, dendritic cell accumulation, and endothelial activation. Development of this phenotype requires the activation of the Th17 subset of T cells, shown previously to be central to psoriasis. Moreover, gene dysregulation in the transgenic mice is highly similar to that in psoriasis. Key transcriptional programs activated in psoriasis, including IL1-related signalling and cholesterol biosynthesis, are replicated in the mouse model, suggesting that PPARbeta/delta regulates these transcriptional changes in psoriasis. Finally, we identify phosphorylation of STAT3 as a novel pathway activated by PPARbeta/delta and show that inhibition of STAT3 phosphorylation blocks disease development. CONCLUSIONS: Activation of PPARbeta/delta in the epidermis is sufficient to trigger inflammatory changes, immune activation, and signalling, and gene dysregulation characteristic of psoriasis.

Wnt5a exhibits layer-specific expression in adult skin, is upregulated in psoriasis, and synergizes with type 1 interferon.

BACKGROUND: Wnt5a is a member of the wingless-type patterning regulators important in pre-natal development. The expression and distribution of Wnt5a and its receptors frizzled (fzd) 3 and fzd 5 in adult human skin have not been comprehensively studied to date. METHODOLOGY/PRINCIPAL FINDINGS: We here show that Wnt5a, fzd3, fzd5, as well as fzd6 are restricted to specific layers in normal epidermis, analogous to their zonal distribution in hair follicles, suggesting a role in adult skin differentiation. In line, Wnt5a and fzd5 are both overexpressed and re-distributed in the epidermis of psoriasis which involves disturbed keratinocyte differentiation. Functionally, Wnt5a lowers the concentration of IFN required to induce target genes, and increases the magnitude of IFN target gene induction, suggesting a molecular mechanism underlying IFN hypersensitivity in psoriasis. Finally, we identify nedd8 and the amyloid precursor APP, previously shown to be upregulated in psoriasis, as targets of synergistic IFNalpha/Wnt5a induction. CONCLUSIONS/SIGNIFICANCE: The present data (i) suggest that Wnt5a regulates epidermal differentiation even in adult skin and (ii) identify synergistic induction of type 1 IFN target genes as a novel mode of Wnt5a action. Targeting Wnt5a in the skin may reduce IFN hypersensitivity and be of therapeutical value.

Protein phosphatase 2A and rapamycin regulate the nuclear localization and activity of the transcription factor GLI3.

Gain-of-function alterations to the sonic hedgehog (SHH) signaling cascade have been found in a wide range of tumors. Three SHH effectors, GLI1, GLI2, and GLI3, regulate transcription of diverse genes involved in cell growth and cell proliferation. Here, we show that protein phosphatase 2A (PP2A), its regulatory subunit, alpha4, and rapamycin, an inhibitor of the mammalian target of rapamycin kinase complex 1 (mTORC1), regulate the nuclear localization and transcriptional activity of GLI3. An increase in PP2A activity or treatment with rapamycin leads to cytosolic retention of GLI3 and, consequently, reduced transcription of the GLI3 target gene and cell cycle regulator, cyclin D1. Conversely, inhibition of PP2A results in increased expression of cyclin D1. In summary, our findings reveal the existence of a hitherto unrecognized molecular cross-talk between the oncogenic SHH pathway and the tumor suppressor PP2A and suggest a novel mechanism underlying the anticancerogenic effects of rapamycin.

PPARdelta is a type 1 IFN target gene and inhibits apoptosis in T cells.

Peroxisome proliferator-activated receptor beta/delta (PPARdelta) is a nuclear hormone receptor regulating diverse biological processes, including beta-oxidation of fatty acid and epithelial cell differentiation. To date, the role of PPARdelta in the immune system has not been thoroughly studied. Here, we show that PPARdelta is expressed in activated human T cells purified from peripheral blood as well as in T cells isolated from affected psoriasis skin lesions. PPARdelta is induced in T cells on stimulation with type 1 IFN. Functionally, PPARdelta enhances proliferation of primary T cells and blocks apoptosis induced by type 1 IFN and by serum deprivation. We show that these cellular functions are mediated by the activation of extracellular signal-regulated kinase1/2 signaling. Our results (1) establish a direct molecular link between type 1 IFN signaling and PPARdelta, (2) define a functional role for PPARdelta in human T cells, and (3) suggest that the induction of PPARdelta by type 1 IFN contributes to the persistence of activated T cells in psoriasis skin lesions.

PPARdelta enhances keratinocyte proliferation in psoriasis and induces heparin-binding EGF-like growth factor.

Psoriasis is a common skin disease involving keratinocyte proliferation and altered differentiation, as well as T-cell activation. Here, we show that altered gene transcription in psoriatic skin lesions is highly reproducible between independent data sets. Analysis of gene expression confirmed dysregulation in all expected functional categories, such as IFN signaling and keratinocyte differentiation, and allowed molecular fingerprinting of a previously characterized dendritic cell subset associated with psoriasis tumor necrosis factor alpha (TNF-alpha)- and inducible nitric oxide synthase (iNOS)-producing CD11b(INT) DC (Tip-DC). Unexpectedly, a large group of dysregulated transcripts was related to fatty acid signaling and adipocyte differentiation, exhibiting a pattern consistent with the activation of peroxisome proliferator-activated receptor delta (PPARdelta). PPARdelta itself was strongly induced in psoriasis in vivo. In primary keratinocytes, PPARdelta was induced by the transcription factor activator protein 1, in particular by junB, but not by canonical WNT signaling, in contrast to its regulation in colon carcinoma cells. Activation of PPARdelta enhanced proliferation of keratinocytes, while this was inhibited by knockdown of PPARdelta. Finally, heparin-binding EGF-like growth factor (HB-EGF), known to induce epidermal hyperplasia and itself overexpressed in psoriasis, was identified as a direct target gene of PPARdelta. The present data suggest that activation of PPARdelta is a major event in psoriasis, contributing to the hyperproliferative phenotype by induction of HB-EGF.

Optimized production and concentration of lentiviral vectors containing large inserts.

Generation of high titer lentiviral stocks and efficient virus concentration are central to maximize the utility of lentiviral technology. Here we evaluate published protocols for lentivirus production on a range of transfer vectors differing in size (7.5-13.2 kb). We present a modified virus production protocol robustly yielding useful titers (up to 10(7)/ml) for a range of different transfer vectors containing packaging inserts up to 7.5 kb. Moreover, we find that virus recovery after concentration by ultracentrifugation depends on the size of the packaged inserts, heavily decreasing for large packaged inserts. We describe a fast (4 h) centrifugation protocol at reduced speed allowing high virus recovery even for large and fragile lentivirus vectors. The protocols outlined in the current report should be useful for many labs interested in producing and concentrating high titer lentiviral stocks.

A cold-response index for the assessment of Raynaud's phenomenon.

BACKGROUND: Quantification of Raynaud's phenomenon (RP) is a prerequisite in the evaluation of novel therapeutic strategies. Fingertip rewarming in response to local cold provocation has been used in many studies but not been systematically validated. We have previously described the time elapsed before 63% of pre-cooling temperature is reached as a RP activity index. OBJECTIVE: A comprehensive evaluation of fingertip rewarming in primary and scleroderma-associated RP. METHODS: We defined a cold-response index (CRI) as the log transformation of the 63% rewarming time upon cold challenge. RESULTS: The CRI shows high intra-individual reproducibility. The mean CRI values were (mean+/-S.D.): 2.4+/-0.3 in controls (n=53) versus 2.7+/-0.3 in RP (n=50, p<0.0001 versus controls), and 2.7+/-0.3 in scleroderma patients (n=46, p<0.0001). In addition, baseline fingertip temperature was also found to be significantly reduced both in primary as well as scleroderma-associated RP. Kinetic analysis of rewarming temperature curves demonstrates that the CRI is independent of individual rewarming patterns. Finally, the CRI decreases significantly upon a single low-level systemic hyperthermia treatment in scleroderma patients (2.68+/-0.28 before versus 2.45+/-0.33 after, p=0.0003), while the extent of cooling remained unchanged, thus demonstrating sensitivity to change. CONCLUSION: Our results provide a solid basis for using the cold-response assay as an endpoint in addition to clinical activity scores in RP treatment trials.