Angiogenesis drives psoriasis pathogenesis

Psoriasin (S100A7) promotes stress-induced angiogenesis

BACKGROUND

Vascular modifications occur early in the development of psoriasis, and angiogenesis is one of the key features in the pathogenesis of the disease.

OBJECTIVES

To identify the role of the S100 protein psoriasin in psoriasis-associated angiogenesis.

METHODS

The role of psoriasin in mediating angiogenesis was investigated by silencing psoriasin with small interfering RNA (siRNA) and measuring psoriasis-associated angiogenic factors in human epidermal keratinocytes. The secretion of psoriasin and the effect of psoriasin on general regulators of angiogenesis in keratinocytes, and on endothelial cell migration, proliferation, tube formation and production of angiogenic mediators, was evaluated.

RESULTS

Reactive oxygen species (ROS) and hypoxia induced the expression of psoriasin. Downregulation of psoriasin in keratinocytes using siRNA altered the ROS-induced expression of the psoriasis-associated angiogenic factors vascular endothelial growth factor (VEGF), heparin-binding epidermal growth factor-like growth factor, matrix metalloproteinase 1 and thrombospondin 1. Overexpression of psoriasin altered several regulators of angiogenesis and led to the secretion of psoriasin. Treatment with extracellular psoriasin induced proliferation, migration and tube formation in dermal-derived endothelial cells to a similar extent as VEGF and interleukin-17, and induced the expression and release of proangiogenic mediators. These effects were suggested to be mediated by the PI3K and nuclear factor kappa B pathways.

CONCLUSIONS

These findings suggest that psoriasin expression is promoted by oxidative stress in keratinocytes and amplifies the ROS-induced expression of angiogenic factors relevant to psoriasis. Moreover, extracellularly secreted psoriasin may act on dermal endothelial cells to contribute to key features angiogenesis.

Upregulation of ANGPTL6 in mouse keratinocytes enhances susceptibility to psoriasis

Psoriasis is a chronic inflammatory skin disease marked by aberrant tissue repair. Mutant mice modeling psoriasis skin characteristics have provided useful information relevant to molecular mechanisms and could serve to evaluate therapeutic strategies. Here, we found that epidermal ANGPTL6 expression was markedly induced during tissue repair in mice. Analysis of mice overexpressing ANGPTL6 in keratinocytes (K14-Angptl6 Tg mice) revealed that epidermal ANGPTL6 activity promotes aberrant epidermal barrier function due to hyperproliferation of prematurely differentiated keratinocytes. Moreover, skin tissues of K14-Angptl6 Tg mice showed aberrantly activated skin tissue inflammation seen in psoriasis. Levels of the proteins S100A9, recently proposed as therapeutic targets for psoriasis, also increased in skin tissue of K14-Angptl6 Tg mice, but psoriasis-like inflammatory phenotypes in those mice were not rescued by S100A9 deletion. This finding suggests that decreasing S100A9 levels may not ameliorate all cases of psoriasis and that diverse mechanisms underlie the condition. Finally, we observed enhanced levels of epidermal ANGPTL6 in tissue specimens from some psoriasis patients. We conclude that the K14-Angptl6 Tg mouse is useful to investigate psoriasis pathogenesis and for preclinical testing of new therapeutics. Our study also suggests that ANGPTL6 activation in keratinocytes enhances psoriasis susceptibility.

The effect of etanercept on vascular endothelial growth factor production by cutaneous mesenchymal stem cells from patients with psoriasis

OBJECTIVE

To evaluate prospectively the effect of etanercept (a tumour necrosis factor [TNF]-α inhibitor) on vascular endothelial growth factor (VEGF) production by mesenchymal stem cells (MSC) from patients with psoriasis.

METHODS

MSCs from lesional and perilesional skin were isolated, cultured and characterized. VEGF production was evaluated at baseline and after 12 weeks' etanercept treatment.

RESULTS

Etanercept treatment resulted in significant reductions in VEGF production compared with baseline in both lesional MSCs (256.42 ± 3.07 pg/ml per 10⁶ cells at baseline vs 27.66 ± 2.03 pg/ml per 10⁶ cells after treatment) and perilesional MSCs (235.03 ± 2.52 pg/ml per 10⁶ cells vs 41.65 ± 4.72 pg/ml per 10⁶ cells).

CONCLUSIONS

Etanercept reduces the production of VEGF in MSCs, which may modulate angiogenesis and contributes towards preventing the start of the "psoriatic march".

Haptoglobin protein and mRNA expression in psoriasis and its clinical significance

The present study aimed to explore the association between haptoglobin protein and mRNA expression and psoriasis. A total of 138 patients with psoriasis that were undergoing therapy at Linyi People's Hospital (Linyi, China) between January 2011 and January 2015 were enrolled in the present study. The mRNA expression levels of haptoglobin were detected by in situ hybridization; immunohistochemistry was used to detect haptoglobin protein expression; and double‑labeling immunofluorescence was used to count Langerhans cells; western blotting was also conducted to determine protein expression. A receiver operating characteristic (ROC) curve was generated to assess the diagnostic value of haptoglobin for psoriasis. Compared with the normal and negative control (NC) groups, the mRNA expression levels of haptoglobin were markedly increased in the experimental group (P<0.05). Haptoglobin protein expression was also markedly increased in the experimental group compared with in the normal and NC groups (P<0.05). Conversely, there was no significant difference in haptoglobin expression between the NC group and the normal group (P>0.05). The critical value of haptoglobin mRNA in the diagnosis of psoriasis was 2.93, and sensitivity and specificity were 91.3 and 73.6%, respectively. The area under the ROC curve was 0.883 [95% confidence interval (CI)=0.837‑0.929]. The critical value of haptoglobin protein in the diagnosis of psoriasis was 0.995, and sensitivity and specificity were 76.1 and 99.9%, respectively. The area under the ROC curve was 0.926 (95% CI=0.837‑0.929). The present study demonstrated that the mRNA and protein expression levels of haptoglobin were increased in patients with psoriasis. Haptoglobin mRNA and protein expression were closely associated with the occurrence of psoriasis; therefore, haptoglobin may be considered a promising novel clinical indicator for the diagnosis of psoriasis.

Plants and their active compounds: natural molecules to target angiogenesis

Angiogenesis, or new blood vessel formation, is an important process in the pathogenesis of several diseases and thus has been targeted for the prevention and treatment for many disorders. However, the anti-angiogenic agents that are currently in use are mainly synthetic compounds and humanized monoclonal antibodies, which are either expensive or toxic, thereby limiting their use in many patients. Therefore, it is necessary to identify less toxic, inexpensive, novel and effective anti-angiogenic molecules. Several studies have indicated that natural plant products can meet these criteria. In this review, we discuss the anti-angiogenic properties of natural compounds isolated from plants and the molecular mechanisms by which these molecules act. Finally, we summarize the advantages of using plant products as anti-angiogenic agents. Compared with currently available anti-angiogenic drugs, plant products may not only have similar therapeutic potential but are also inexpensive, less toxic, and easy to administer. However, novel and effective strategies are necessary to improve their bioavailability for clinical use.

Recent advances in understanding psoriasis

T helper (Th) cells producing interleukin (IL)-17, IL-22, and tumor necrosis factor (TNF) form the key T cell population driving psoriasis pathogenesis. They orchestrate the inflammation in the skin that results in the proliferation of keratinocytes and endothelial cells. Besides Th17 cells, other immune cells that are capable of producing IL-17-associated cytokines participate in psoriatic inflammation. Recent advances in psoriasis research improved our understanding of the cellular and molecular players that are involved in Th17 pathology and inflammatory pathways in the skin. The inflammation-driving actions of TNF in psoriasis are already well known and antibodies against TNF are successful in the treatment of Th17-mediated psoriatic skin inflammation. A further key cytokine with potent IL-17-/IL-22-promoting properties is IL-23. Therapeutics directly neutralizing IL-23 or IL-17 itself are now extending the therapeutic spectrum of antipsoriatic agents and further developments are on the way. The enormous progress in psoriasis research allows us to control this Th17-mediated inflammatory skin disease in many patients.

Oxidative stress in psoriasis and potential therapeutic use of antioxidants

The pathophysiology of psoriasis is complex and dynamic. Recently, the involvement of oxidative stress in the pathogenesis of psoriasis has been proposed. Oxidative stress is an imbalance between oxidants and antioxidants in favor of the oxidants, leading to a disruption of redox signaling and control and/or molecular damage. In this article, the published studies on the role of oxidative stress in psoriasis pathogenesis are reviewed, focusing on the impacts of oxidative stress on dendritic cells, T lymphocytes, and keratinocytes, on angiogenesis and on inflammatory signaling (mitogen-activated protein kinase, nuclear factor-κB, and Janus kinase/signal transducer and activator of transcription). As there is compelling evidence that oxidative stress is involved in the pathogenesis of psoriasis, the possibility of using this information to develop novel strategies for treatment of patients with psoriasis is of considerable interest. In this article, we also review the published studies on treating psoriasis with antioxidants and drugs with antioxidant activity.

Evaluation of Macular Ganglion Cell-inner Plexiform Layer and Choroid in Psoriasis Patients Using Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography

PURPOSE

To evaluate changes in the thickness of the central macula, macular ganglion cell-inner plexiform layer (mGCIPL), and subfoveal choroid in patients with psoriasis using spectral domain optical coherence tomography (SD-OCT).

METHODS

The measurements of macular, mGCIPL thicknesses and subfoveal choroidal thickness (SFCT) obtained by SD-OCT of psoriasis patients (n = 46). These measurements were compared with those of 50 healthy controls.

RESULTS

The macular, mGCIPL, and choroidal thicknesses did not differ between the controls and psoriatic subjects (p>0.05). When the patients were divided into two distinct groups, only the SFCT was significantly thicker in the severe psoriasis group compared with the mild psoriasis group (p = 0.003).

CONCLUSIONS

These findings suggest that choroidal alterations are seen without macular changes in patients with psoriasis. Severe psoriasis appears to be related to increases in SFCT as a consequence of possible inflammatory cascades that are part of the disease's pathogenesis.

Inhibition of imiquimod-induced psoriasis-like dermatitis in mice by herbal extracts from some Indian medicinal plants

Psoriasis is a chronic autoimmune human skin disorder that is characterized by excessive proliferation of keratinocytes, scaly plaques, severe inflammation and erythema. The pathophysiology of psoriasis involves interplay between epidermal keratinocytes, T lymphocytes, leukocytes and vascular endothelium. Increased leukocyte recruitment and elevated levels of cytokines, growth factors and genetic factors like interleukin (IL)-1β, IL-6, IL-17, IL-22, IL-23, tumour necrosis factor (TNF)-α, interferon (IFN)-γ, transforming growth factor (TGF)-β, toll-like receptor (TLR)-2, signal transducer and activator of transcription (STAT-3), 15-lipoxygenase (LOX)-2, coiled-coil alpha-helical rod protein 1 (CCHCR1), steroidogenic acute regulatory protein (StAR) and vitamin D receptor (VDR) are the most critical factors governing the exacerbation of psoriasis. In the present study, an attempt was made to elucidate the preventive role of herbal extracts of four dermo-protective Ayurvedic plants, Tinospora cordifolia (TC), Curcuma longa (CL), Celastrus paniculatus (CP) and Aloe vera (AV), against psoriasis-like dermatitis. Parkes (P) strain mice were initially induced with psoriasis-like dermatitis using topical application of imiquimod (IMQ, 5 %), followed by subsequent treatment with the herbal extracts to examine their curative effect on the psoriasis-like dermatitis-induced mice. The extracts were orally/topically administered to mice according to their ED/LD50 doses. Phenotypical observations, histological examinations, and semi-quantitative reverse transcription PCR (RT-PCR) analyses of the skin and blood samples of the control, IMQ-treated and herbal extract-treated psoriasis-like dermatitis-induced mice lead to the conclusion that the combination extract from all the plants was instrumental in downregulating the overexpressed cytokines, which was followed by the CL extract. Moreover, lesser yet positive response was evident from CP and TC extracts. The results suggest that these plants can prove to have tremendous preventive potential against the disease and can open the way to new therapeutic strategies for psoriasis treatment.

Genetic Risk Factors for Psoriasis in Turkish Population: -1540 C/A, -1512 Ins18, and +405 C/G Polymorphisms within the Vascular Endothelial Growth Factor Gene

Background

Evidence regarding the vascular endothelial growth factor A (VEGFA) as a potent mediator of angiogenesis and inflammation in psoriasis has revealed variations in this gene as surrogate markers of psoriasis.

Objective

VEGFA gene polymorphisms (-1540 C/A, -1512 Ins18, -460 T/C, and +405 C/G) in psoriasis susceptibility in Turkish population were investigated.

Methods

A total of 200 age, sex and ethnicity-matched psoriatic and healthy individuals were examined for clinical type, response to therapy, serum VEGFA and its receptor levels, genotypes and haplotypes.

Results

The +405 GG, +405 CG, -1540 CA, and -1512 +Ins18 genotypes conferred a significant risk for developing psoriasis. The C-InsTC haplotype in the controls and C+InsTG, A+InsTC, and A-InsTG haplotypes in psoriatic patients were observed to be significantly high. Increased serum levels of VEGFA were detected in psoriatic patients with the C-InsTC haplotype than that in the controls. The +405 GG genotype was significantly more frequent in psoriatic patients with a positive family history, and the moderate form of psoriasis was more frequent among C+InsTG haplotype carriers than that among the other patients. The +405 GG genotype was found to be more frequent in patients responding to oral retinoids. Serum VEGFR1/FLT1 and VEGFR2/KDR levels were not significantly different when psoriatic patients and controls were stratified based on the risk polymorphic variants.

Conclusion

VEGFA gene +405 GG and CG, -1512+Ins18, and -1540 CA genotypes are associated with an increased risk of psoriasis in Turkish population. The G allele at +405 and an 18-bp insertion at -1512 are primarily the risk factors for psoriasis, and this risk is potentiated by the presence of the A allele at the -1540 locus.

The role of hormones in the pathogenesis of psoriasis vulgaris

Psoriasis vulgaris is a chronic, common skin disease, which affects the patient’s quality of life to the highest degree. Several exogenous factors and endogenous hormonal changes may act as triggers for psoriasis.

The skin possesses a true endocrine system, which is very important in multiple systemic diseases. A number of conditions are associated with psoriasis, and its severity can also be influenced by hormones. Even though the sex hormones and prolactin have a major role in psoriasis pathogenicity, there are a lot of other hormones which can influence the psoriasis clinical manifestations: glucocorticoids, epinephrine, thyroid hormones, and insulin.

Expression of pro-angiogenic genes in mesenchymal stem cells derived from dermis of patients with psoriasis

BACKGROUND

Recent experimental studies revealed that angiogenesis and lymphangiogenesis are closely related to psoriasis. Our microarray analysis suggested that the pro-angiogenic genes platelet endothelial cell adhesion molecule-1 (PECAM1), facio-genital dysplasia-5 (FGD5), prostaglandin-endoperoxide synthase-1 (PTGS1), melanoma cell adhesion molecule (MCAM), vasohibin-2 (VASH2), and stabilin-1 (STAB1) are differentially expressed in dermal mesenchymal stem cells in psoriasis.

OBJECTIVES

The aim of this study was to investigate the mRNA and protein expression of PECAM1, FGD5, PTGS1, MCAM, VASH2, and STAB1 for angiogenesis and the possible mechanisms in psoriasis.

METHODS

We studied 12 patients with plaque psoriasis and 14 healthy controls matched for age and sex. Dermal mesenchymal stem cells were expanded, passaged, and identified by cellular morphology, immunophenotyping, and multipotential differentiation. The mRNA and protein expression of the above-mentioned six genes were confirmed by quantitative real-time reverse transcription-polymerase chain reaction and Western blotting.

RESULTS

The significantly decreased expression of PECAM1, PTGS1, FGD5, and MCAM at both mRNA and protein level (except VASH2 and STAB1) were demonstrated in mesenchymal stem cells from psoriatic skin lesions compared with non-lesional from healthy controls.

CONCLUSIONS

We provide the first report that pro-angiogenic genes PECAM1, PTGS1, FGD5, and MCAM rather than VASH2 and STAB1 may be play a vital role in pathological dermal angiogenesis disorders of psoriasis. Therefore, anti-angiogenesis is attractive and offers future potential for application in patients with psoriasis.

mRNA and protein expression of the angiogenesis-related genes EDIL3, AMOT and ECM1 in mesenchymal stem cells in psoriatic dermis

BACKGROUND

Dermal microvasculature expansion and angiogenesis are prominent in psoriasis. Our previous microarray study showed that the angiogenesis-related genes EDIL3 (epidermal growth factor-like repeats and discoidin I-like domains 3), AMOT (angiomotin) and ECM1 (extracellular matrix protein 1), had high expression levels in dermal mesenchymal stem cells (DMSCs) from psoriatic skin lesions.

AIM

To investigate the mRNA and protein expressions of EDIL3, AMOT and ECM1 in DMSCs derived from psoriatic skin in order to better determine the molecular mechanisms of angiogenesis in the skin.

METHODS

DMSCs from 12 patients with psoriasis and 14 healthy controls (HCs) were cultured to passage 3, and identified by morphology, immunophenotype and multipotential differentiation. The mRNA and protein expressions of EDIL3, AMOT, and ECM1 in the DMSCs were determined using real-time reverse transcription PCR and western blotting.

RESULTS

DMSCs displayed spindle-like morphology and surface protein expression, and were able to differentiate into osteoblasts, chondrocytes and adipocytes. mRNA expression analysis showed that EDIL3, AMOT and ECM1 were expressed at 2.54-fold, 2.11-fold, and 1.90-fold higher levels, respectively, in psoriatic DMSCs compared with HC DMSCs (all P < 0.05). Protein analysis showed significantly (all P < 0.01) higher concentrations of EDIL3, AMOT and ECM1in the psoriasis group than in the HC group.

CONCLUSIONS

Our data demonstrate for the first time that expression of EDIL3, AMOT and ECM1 is altered in DMSCs in psoriasis, suggesting that EDIL3, AMOT and ECM1 are involved in the excessive angiogenesis and vasodilation observed in psoriasis.

18F-FP-PEG2-β-Glu-RGD2: A Symmetric Integrin αvβ3-Targeting Radiotracer for Tumor PET Imaging

Radiolabeled cyclic arginine-glycine-aspartic (RGD) peptides can be used for noninvasive determination of integrin α_vβ₃ expression in tumors. In this study, we performed radiosynthesis and biological evaluation of a new ¹⁸F-labeled RGD homodimeric peptide with one 8-amino-3,6-dioxaoctanoic acid (PEG₂) linker on the glutamate β-amino group (¹⁸F-FP-PEG₂-β-Glu-RGD₂) as a symmetric PET tracer for tumor imaging. Biodistribution studies showed that radioactivity of ¹⁸F-FP-PEG₂-β-Glu-RGD₂ was rapidly cleared from blood by predominately renal excretion. MicroPET-CT imaging with ¹⁸F-FP-PEG₂-β-Glu-RGD₂ revealed high tumor contrast and low background in A549 human lung adenocarcinoma-bearing mouse models, PC-3 prostate cancer-bearing mouse models, and orthotopic transplanted C6 brain glioma models. ¹⁸F-FP-PEG₂-β-Glu-RGD₂ exhibited good stability in vitro and in vivo. The results suggest that this tracer is a potential PET tracer for tumor imaging.

Oral fumaric acid esters for psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory skin condition that can markedly reduce life quality. Several systemic therapies exist for moderate to severe psoriasis, including oral fumaric acid esters (FAE). These contain dimethyl fumarate (DMF), the main active ingredient, and monoethyl fumarate. FAE are licensed for psoriasis in Germany but used off-licence in many countries.

OBJECTIVES

To assess the effects and safety of oral fumaric acid esters for psoriasis.

SEARCH METHODS

We searched the following databases up to 7 May 2015: the Cochrane Skin Group Specialised Register, CENTRAL in the Cochrane Library (Issue 4, 2015), MEDLINE (from 1946), EMBASE (from 1974), and LILACS (from 1982). We searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials. We handsearched six conference proceedings that were not already included in the Cochrane Skin Group Specialised Register.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of FAE, including DMF monotherapy, in individuals of any age and sex with a clinical diagnosis of psoriasis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Primary outcomes were improvement in Psoriasis Area and Severity Index (PASI) score and the proportion of participants discontinuing treatment due to adverse effects.

MAIN RESULTS

We included 6 studies (2 full reports, 2 abstracts, 1 brief communication, and 1 letter), with a total of 544 participants. Risk of bias was unclear in several studies because of insufficient reporting. Five studies compared FAE with placebo, and one study compared FAE with methotrexate. All studies reported data at 12 to 16 weeks, and we identified no longer-term studies. When FAE were compared with placebo, we could not perform meta-analysis for the primary outcome of PASI score because the three studies that assessed this outcome reported the data differently, although all studies reported a significant reduction in PASI scores with FAE. Only 1 small study designed for psoriatic arthritis reported on the other primary outcome of participants discontinuing treatment due to adverse effects (2 of 13 participants on FAE compared with none of the 14 participants on placebo; risk ratio (RR) 5.36, 95% confidence interval (CI) 0.28 to 102.1; 27 participants; very low-quality evidence). However, these findings are uncertain due to indirectness and a very wide confidence interval. Two studies, containing 247 participants and both only reported as abstracts, allowed meta-analysis for PASI 50, which showed superiority of FAE over placebo (RR 4.55, 95% CI 2.80 to 7.40; low-quality evidence), with a combined PASI 50 of 64% in those given FAE compared with a PASI 50 of 14% for those on placebo, representing a number needed to treat to benefit of 2. The same studies reported more participants achieving PASI 75 with FAE, but we did not pool the data because of significant heterogeneity; none of the studies measured PASI 90. One study reported significant improvement in participants' quality of life (QoL) with FAE, measured with Skindex-29. However, we could not compute the mean difference because of insufficient reporting in the abstract. More participants experienced adverse effects, mainly gastrointestinal disturbance and flushing, on FAE (RR 4.72, 95% CI 2.45 to 9.08; 1 study, 99 participants; moderate-quality evidence), affecting 76% of participants given FAE and 16% of the placebo group (representing a number needed to treat to harm of 2). The other studies reported similar findings or did not report adverse effects fully.One study of 54 participants compared methotrexate (MTX) with FAE. PASI score at follow-up showed superiority of MTX (mean Difference (MD) 3.80, 95% CI 0.68 to 6.92; 51 participants; very low-quality evidence), but the difference was not significant after adjustment for baseline disease severity. The difference between groups for the proportion of participants who discontinued treatment due to adverse effects was uncertain because of imprecision (RR 0.19, 95% CI 0.02 to 1.53; 1 study, 51 participants; very low-quality evidence). Overall, the number of participants experiencing common nuisance adverse effects was not significantly different between the 2 groups, with 89% of the FAE group affected compared with 100% of the MTX group (RR 0.89, 95% CI 0.77 to 1.03; 54 participants; very low-quality evidence). Flushing was more frequent in those on FAE, with 13 out of 27 participants affected compared with 2 out of 27 given MTX. There was no significant difference in the number of participants who attained PASI 50, 75, and 90 in the 2 groups (very low-quality evidence) whereas this study did not measure the effect of treatments on QoL. The included studies reported no serious adverse effects of FAE and were too small and of limited duration to provide evidence about rare or delayed effects.

AUTHORS' CONCLUSIONS

Evidence suggests that FAE are superior to placebo and possibly similar in efficacy to MTX for psoriasis; however, the evidence provided in this review was limited, and it must be noted that four out of six included studies were abstracts or brief reports, restricting study reporting. FAE are associated with nuisance adverse effects, including flushing and gastrointestinal disturbance, but short-term studies reported no serious adverse effects.

Anti-TNF-α monoclonal antibody reverses psoriasis through dual inhibition of inflammation and angiogenesis

Tumor necrosis factor-alpha (TNF-α) antagonists have shown remarkable efficacy in psoriasis; however, the precise mechanisms of action of TNF-α blocking agents mainly focus on their neutralizing TNF-α and its anti-inflammatory effects. In this study, we generated a humanized anti-TNF-α monoclonal antibody (IBI303) and suggested a potential mechanism of anti-TNF-α therapy for psoriasis. The results of SPR and ELISA indicated that IBI303 has a good affinity to TNF-α. In vitro, it could suppress TNF-α-induced cytotoxicity in WEHI164 cells. In vivo, administration of IBI303 to K14-VEGF transgenic mice led to a significant treatment efficiency in psoriasis in a dose-dependent manner. IHC staining and cytokines-ELISA indicated that TNF-α inhibition strongly reduced inflammatory cells infiltration and pro-inflammatory cytokines release, accompanied by suppression of inflamed dermal blood vessels. Mechanistically, in order to explain the anti-angiogenesis effect of anti-TNF-α antibody, the production of cytokine in macrophage conditional medium was measured by ELISA. The result indicated that the massive secretion of TNF-α stimulated by LPS in RAW264.7 cell supernatant was markedly neutralized in a dose-response manner by IBI303, moreover, the expression of NF-κB p65 was down-regulated. Mouse endothelial cell tube formation assay showed that anti-TNF-α could inhibit blood vessels formation directly and indirectly. Collectively, our study suggested a kind of antipsoriatic mechanism of TNF-α inhibitors that is the dual inhibition of inflammation and angiogenesis.

Dimethylfumarate protects against TNF-α-induced secretion of inflammatory cytokines in human endothelial cells

Background

Inflammation, angiogenesis and oxidative stress have been implicated in the pathogenesis of various vascular diseases. Recent evidence suggests that dimethylfumarate (DMF), an antiposriatic and anti-multiple sclerosis agent, possesses anti-inflammatory, anti-oxidative and anti-angiogenic properties. Here, we analyze the influence of DMF on TNF-α-induced expression of the important pro-inflammatory and pro-atherogenic chemokine MCP-1 and investigate the underlying mechanisms of this expression.

Findings

We analyzed constitutive and TNF-α-induced expression of MCP-1 in human umbilical vascular endothelial cells (HUVEC) +/− DMF treatment via enzyme-linkes immunosorbent assay (ELISA). DMF significantly inhibited the protein expression levels in a time- and concentration-dependent manner. Furthermore, MCP-1 mRNA expression was also reduced in response to DMF, as demonstrated by RT-PCR. Thus, the regulation occurs at the transcriptional level. Interestingly, DMF prolonged the TNF-α-induced p38 and JNK phosphorylation in HUVEC, as demonstrated by Western blot analysis; however, the p38 and JNK inhibitor SB203580 did not affect the DMF-conveyed suppression of TNF-α-induced MCP-1 expression. DMF suppressed the TNF-α-induced nuclear translocation and phosphorylation (Serine 536) of p65 in these cells. These results were additionally approved by p65 luciferase promoter assays. Furthermore, we found that DMF slightly inhibited the early degradation of IκBα. In addition, we verified our results using other important inflammatory cytokines such as CCL-5, PDGF-BB, GM-CSF and IL-6.

Conclusion

DMF suppresses various TNF-α-induced pro-inflammatory and pro-atherogenic cytokines/chemokines in human endothelial cells. This action is regulated by reduced p65 activity and nuclear translocation, which can be explained in part by the reduced early degradation of IκBα and more important the reduced phosphorylation of p65 at Serine 536. These effects were independent of the p38, PI3K and p42/44 signaling pathways. As a result, DMF might be suitable for treating patients with vascular diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0094-z) contains supplementary material, which is available to authorized users.

Inflammation and Neovascularization in Hip Impingement: Not Just Wear and Tear

BACKGROUND

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis (OA) in young active patients, but the pathophysiology remains unclear. Increasingly, mechanistic studies point toward an inflammatory component in OA.

PURPOSE

This study aimed to characterize inflammatory cell subtypes and neovascularization in FAI by exploring the phenotype and quantification of inflammatory cells and neovascularization in FAI versus OA samples.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten samples of the labrum were obtained from patients with FAI (confirmed diagnosis) during open osteochondroplasty or hip arthroscopic surgery. Control samples of the labrum were collected from 10 patients with OA who were undergoing total hip arthroplasty. Labral biopsy specimens were evaluated immunohistochemically by quantifying the presence of macrophages (CD68, CD206, interleukin-13 [IL-13]), T cells (CD3), mast cells (mast cell tryptase), and vascular endothelium (CD34, vascular endothelial growth factor).

RESULTS

Labral biopsy specimens obtained from patients with FAI exhibited significantly greater macrophage, mast cell, and vascular endothelium expression compared with control OA labral samples (P < .05). The most significant difference was noted in macrophage (P < .01) and mast cell (P < .05) expression. Further subtyping of macrophages in FAI using the CD206 tissue marker and IL-13 revealed an M2 phenotype, suggesting that these cells are involved in a regenerate versus degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r = 0.4, P < .01) in FAI samples.

CONCLUSION

This study provides evidence for an inflammatory cell infiltrate in FAI along with significant neovascularization. In particular, the significant infiltration of mast cells and macrophages was demonstrated, suggesting a role for innate immune pathways in the events that mediate hip impingement.

CLINICAL RELEVANCE

Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.

VEGF involvement in psoriasis

Vascular endothelial growth factor (VEGF) is a key growth factor, regulating the neovascularization, during embryogenesis, skeletal growth, reproductive functions and pathological processes. The VEGF receptors (VEGFR) are present in endothelial cells and other cell types, such as vascular smooth muscle cells, hematopoietic stem cells, monocytes, neurons, macrophages, and platelets. Angiogenesis is initiated by the activation of vascular endothelial cells through several factors. The excess dermal vascularity and VEGF production are markers of psoriasis. The pathological role of VEGF/VEGFR signaling during the psoriasis onset and evolution makes it a promising target for the treatment of psoriasis. Antibodies and other types of molecules targeting the VEGF pathway are currently evaluated in arresting the evolution of psoriasis.

Anti-psoriatic effects of Honokiol through the inhibition of NF-κB and VEGFR-2 in animal model of K14-VEGF transgenic mouse

Honokiol (HK), a biphenolic neolignan isolated from Magnolia officinalis, has been reported to possess anti-inflammatory and anti-angiogenic activaties. In this study, our aim was to investigate anti-psoriatic activities of HK and the involved mechanisms. In vitro, the effects of HK on the regulation of Th1/Th2 and TNF-α-induced NF-κB (p65) activation were analyzed by respective FCS and immunofluorescence. Additionally, the K14-VEGF transgenic model was used for the in vivo study. ELISA and Q-PCR were performed to evaluate serum levels of Th1/Th2 cytokines and their corresponding mRNA expressions. Effects on VEGFR-2 and p65 activation, as well as other angiogenic and inflammatory parameters were studied by immunostainings. Importantly, we found that HK significantly decreased the ratio of Th1/Th2-expression CD4(+) T cells and inhibited TNF-α-induced activation of NF-κB. The morphology and histological features of psoriasis were effectively improved by HK treatment. The expression of TNF-α and IFN-γ, and their corresponding mRNA levels were down-regulated and the expression of nuclear p65, VEGFR-2, as well as related phosphorylated proteins (p-VEGFR-2, p-ERK1/2, p-AKT and p-p38) were also suppressed. Overall, these results in our study suggested that HK exhibits anti-psoriatic effects through the inhibition of NF-κB and VEGFR-2.

Cross Talk between Proliferative, Angiogenic, and Cellular Mechanisms Orchestred by HIF-1α in Psoriasis

Psoriasis is a chronic inflammatory skin disease where the altered regulation in angiogenesis, inflammation, and proliferation of keratinocytes are the possible causes of the disease, and the transcription factor “hypoxia-inducible factor 1-alpha” (HIF-1α) is involved in the homeostasis of these three biological phenomena. In this review, the role of HIF-1α in the cross talk between the cytokines and cells of the immunological system involved in the pathogenesis of psoriasis is discussed.

Obesity exacerbates imiquimod-induced psoriasis-like epidermal hyperplasia and interleukin-17 and interleukin-22 production in mice

Psoriasis is a chronic inflammatory skin disorder that is accompanied by an imbalance between the proliferation and differentiation of keratinocytes. A number of studies have suggested an association between obesity and severe psoriasis; however, it remains to be clarified whether obesity exacerbates psoriasis. To address this unsolved question, we induced psoriasiform dermatitis in mouse models for obesity. We found that obesity exaggerated the severity of psoriasiform dermatitis induced by topical application of the Toll-like receptor (TLR) 7 agonist, imiquimod. Ear swelling and epidermal hyperplasia were more prominent in the obese mice than in the control mice. When compared to imiquimod-treated control mice, imiquimod-treated obese mice expressed higher levels of psoriasis mediators, interleukin-17A (IL-17A) and IL-22 in the skin. Food intake restriction partially abrogated enhanced ear swelling and cytokine overproduction in obese mice. Furthermore, the obesity environment and imiquimod treatment synergistically induced an IL-17A downstream molecule, regenerating islet-derived 3γ (Reg3γ), which is a critical molecule for psoriatic epidermal hyperplasia. Palmitic acid, one of the fatty acids released by subcutaneous adipocytes, increased the expression of REG3A (a human homologue of mouse Reg3γ) in both the HaCaT keratinocyte cell line and normal human keratinocytes. Taken together, these results strongly suggest that obesity exacerbates psoriasiform dermatitis in mice by upregulating IL-17A, IL-22 and Reg3γ.

Telocyte dynamics in psoriasis

The presence of telocytes (TCs) as distinct interstitial cells was previously documented in human dermis. TCs are interstitial cells completely different than dermal fibroblasts. TCs are interconnected in normal dermis in a 3D network and may be involved in skin homeostasis, remodelling, regeneration and repair. The number, distribution and ultrastructure of TCs were recently shown to be affected in systemic scleroderma. Psoriasis is a common inflammatory skin condition (estimated to affect about 0.1-11.8% of population), a keratinization disorder on a genetic background. In psoriasis, the dermis contribution to pathogenesis is frequently eclipsed by remarkable epidermal phenomena. Because of the particular distribution of TCs around blood vessels, we have investigated TCs in the dermis of patients with psoriasis vulgaris using immunohistochemistry (IHC), immunofluorescence (IF), and transmission electron microscopy (TEM). IHC and IF revealed that CD34/PDGFRα-positive TCs are present in human papillary dermis. More TCs were present in the dermis of uninvolved skin and treated skin than in psoriatic dermis. In uninvolved skin, TEM revealed TCs with typical ultrastructural features being involved in a 3D interstitial network in close vicinity to blood vessels in contact with immunoreactive cells in normal and treated skin. In contrast, the number of TCs was significantly decreased in psoriatic plaque. The remaining TCs demonstrated multiple degenerative features: apoptosis, membrane disintegration, cytoplasm fragmentation and nuclear extrusion. We also found changes in the phenotype of vascular smooth muscle cells in small blood vessels that lost the protective envelope formed by TCs. Therefore, impaired TCs could be a 'missed' trigger for the characteristic vascular pathology in psoriasis. Our data explain the mechanism of Auspitz's sign, the most pathognomonic clinical sign of psoriasis vulgaris. This study offers new insights on the cellularity of psoriatic lesions and we suggest that TCs should be considered new cellular targets in forthcoming therapies.

Angiogenesis and lymphangiogenesis in inflammatory skin disorders

Angiogenesis, the growth of new blood vessels from pre-existing vessels, occurs physiologically in wound healing, during inflammatory diseases, and in tumor growth. Lymphangiogenesis can be activated in inflammation and tumor metastasis. The family of vascular endothelial growth factors (VEGFs) and angiopoietins are essential for angiogenesis and lymphangiogenesis. The angiogenic process is tightly regulated by VEGFs, angiopoietins, and endogenous inhibitors. VEGFs and angiopoietins exert their effects by activating specific receptors present on blood and lymphatic endothelial cells. There is now compelling evidence that cells of innate and adaptive immunity (macrophages, mast cells, neutrophils, eosinophils, lymphocytes) are a major source of angiogenic and lymphangiogenic factors. Chronic inflammatory skin diseases such as psoriasis and atopic dermatitis are characterized by altered angiogenesis, lymphangiogenesis, or both. Also such acute inflammatory skin disorders as urticaria, ultraviolet B-induced damage, and angioedema are associated with changes in angiogenic factors. In systemic sclerosis there is a switch from proangiogenic to antiangiogenic factors that play a role in the defective vascular process of this disorder. As yet, there are no clinical trials showing that canonical VEGF/VEGF receptor-targeted strategies can modulate inflammatory skin diseases. Novel strategies targeting other angiogenic/lymphangiogenic pathways should also be investigated.

SWI/SNF chromatin-remodeling enzymes Brahma-related gene 1 (BRG1) and Brahma (BRM) are dispensable in multiple models of postnatal angiogenesis but are required for vascular integrity in infant mice

Background

Mammalian SWItch/Sucrose NonFermentable (SWI/SNF) adenosine triphosphate (ATP)‐dependent chromatin‐remodeling complexes play important roles in embryonic vascular development by modulating transcription of specific target genes. We sought to determine whether SWI/SNF complexes likewise impact postnatal physiological and pathological angiogenesis.

Methods and Results

Brahma‐related gene 1 (BRG1) and Brahma gene (BRM) are ATPases within mammalian SWI/SNF complexes and are essential for the complexes to function. Using mice with vascular‐specific mutations in Brg1 or with a global mutation in Brm, we employed 3 models to test the role of these ATPases in postnatal angiogenesis. We analyzed neonatal retinal angiogenesis, exercise‐induced angiogenesis in adult quadriceps muscles, and tumor angiogenesis in control and mutant animals. We found no evidence of defective angiogenesis in Brg1 or Brm mutants using these 3 models. Brg1/Brm double mutants likewise show no evidence of vascular defects in the neonatal retina or tumor angiogenesis models. However, 100% of Brg1/Brm‐double mutants in which Brg1 deletion is induced at postnatal day 3 (P3) die by P19 with hemorrhaging in the small intestine and heart.

Conclusions

Despite their important roles in embryonic vascular development, SWI/SNF chromatin‐remodeling complexes display a surprising lack of participation in the 3 models of postnatal angiogenesis we analyzed. However, these complexes are essential for maintaining vascular integrity in specific tissue beds before weaning. These findings highlight the temporal and spatial specificity of SWI/SNF activities in the vasculature and may indicate that other chromatin‐remodeling complexes play redundant or more essential roles during physiological and pathological postnatal vascular development.

Expression of lymphatic markers and lymphatic growth factors in psoriasis before and after anti-TNF treatment

BACKGROUND

Angiogenesis is an early stage of psoriatic lesion development, but less is known about lymphagiogenesis and its role in the development of psoriasis.

OBJECTIVE

To examine the expression of specific lymphatic markers and lymphatic growth factors in untreated psoriatic skin, in the unaffected skin of patients and skin of healthy volunteers, as well as their alteration after treatment with an anti-TNF agent.

METHODS

Immunohistochemistry for the lymphatic markers D2-40 and LYVE-1, in addition to the VEGF-C and VEGF-D growth factors, was performed in the skin biopsies of psoriatic lesions and adjacent non-psoriatic skin of 19 patients before and after treatment with etanercept, as well as in the skin biopsies of 10 healthy volunteers.

RESULTS

The expressions of D2-40, VEGF-C and VEGF-D on lymphatic vessels underwent statistically significant increases in untreated psoriatic skin compared with non-lesional skin, in contrast to LYVE-1, which did not involve significant increase in expression in psoriatic skin. VEGF-C expression on lymphatic vessels diminished after treatment with etanercept. Moreover VEGF-C and VEGF-D staining on fibroblasts presented with higher expression in lesional skin than in non-lesional adjacent skin.

CONCLUSION

Remodeling of lymphatic vessels possibly occurs during psoriatic lesion development, parallel to blood vessel formation. The exact role of this alteration is not yet clear and more studies are necessary to confirm these results.

Retinoic Acid promotes interleukin-4 plasmid-dimethylsulfoxide topical transdermal delivery for treatment of psoriasis

Background

Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1-dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system.

Objective

We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14-VEGF) factor transgenic mice.

Methods

After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice.

Results

The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced.

Conclusion

Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly.

[Role of angiostatins in diabetic complications]

Angiogenesis is a process through which new blood vessels form from pre-existing vessels. Angiogenesis is regulated by a number of factors of peptide nature. Disbalance of angiogenic system appears to be the major causative factor contributing vascular abnormalities in diabetes mellitus, resulting in various complications. Angiostatins, which are kringle-containing fragments of plasminogen/plasmin, are known to be powerful physiological inhibitors of neovascularization. In the present review, current literature data on peculiarities of production of angiostatins and their functioning at diabetes mellitus are summarized and analyzed for the first time. Also, role of angiostatins in the pathogenesis of typical diabetic complications, including retinopathies, nephropathies and cardiovascular diseases, is discussed. Data presented in this review may be useful for elaboration of novel effective approaches for diagnostics and therapy of vascular abnormalities in diabetes mellitus.

The neurotrophic receptor Ntrk2 directs lymphoid tissue neovascularization during Leishmania donovani infection

The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80(hi)CD11b(lo)CD11c(+) macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis.

Immature myeloid cells directly contribute to skin tumor development by recruiting IL-17-producing CD4+ T cells

Ortiz et al. report the accumulation of immature myeloid cells in skin tissue of patients with inflammatory conditions, which predisposes to the development of cancer.

Evidence links chronic inflammation with cancer, but cellular mechanisms involved in this process remain unclear. We have demonstrated that in humans, inflammatory conditions that predispose to development of skin and colon tumors are associated with accumulation in tissues of CD33⁺S100A9⁺ cells, the phenotype typical for myeloid-derived suppressor cells in cancer or immature myeloid cells (IMCs) in tumor-free hosts. To identify the direct role of these cells in tumor development, we used S100A9 transgenic mice to create the conditions for topical accumulation of these cells in the skin in the absence of infection or tissue damage. These mice demonstrated accumulation of granulocytic IMCs in the skin upon topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA), resulting in a dramatic increase in the formation of papillomas during epidermal carcinogenesis. The effect of IMCs on tumorigenesis was not associated with immune suppression, but with CCL4 (chemokine [C-C motif] ligand 4)-mediated recruitment of IL-17–producing CD4⁺ T cells. This chemokine was released by activated IMCs. Elimination of CD4⁺ T cells or blockade of CCL4 or IL-17 abrogated the increase in tumor formation caused by myeloid cells. Thus, this study implicates accumulation of IMCs as an initial step in facilitation of tumor formation, followed by the recruitment of CD4⁺ T cells.

Altered chemokine signalling in endothelial progenitor cells from acute ulcerative colitis patients

Ulcerative colitis (UC) is a chronic, idiopathic, inflammatory bowel disease, characterized by alternating stages of clinically active and inactive disease. UC exhibits several inflammatory characteristics, including immune activation, leukocyte infiltration, and altered vascular density. In UC, many of the upregulated inflammatory cytokines are proangiogenic and are released by diverse cell populations, such as infiltrating immune cells and endothelial cells (EC). Increasing evidences suggest that neovascularisation may involve also endothelial progenitor cells (EPCs). In this study we evaluated EPCs recruitment and homing, assessed by CXCR4 expression, in both acute and remitting phase of UC. We report an overall decrease of EPCs in UC patients (controls = 97,94 ± 37,34 cells/mL; acute = 31,10 ± 25,38 cells/mL; remitting = 30,33 ± 19,02 cells/mL; P < 0.001 for both UC groups versus controls). Moreover CXCR4⁺-EPCs, committed to home in inflammatory conditions, were found to be reduced in acute UC patients compared to both remitting patients and controls (acute = 3,13 ± 4,61 cells/mL; controls = 20,12 ± 14,0; remitting = 19,47 ± 12,83; P < 0,001). Interestingly, we found that administration of anti-inflammatory drugs in acute UC is associated with an increase in circulating EPCs, suggesting that this therapy may exert a strong influence on the progenitor cells response to inflammatory processes.

Quantitative comparison of angiogenesis and lymphangiogenesis in cutaneous lichen planus and psoriasis: immunohistochemical assessment

Recent experimental studies revealed that angiogenesis and lymphangiogenesis are closely related to chronic inflammation. The present study aims to evaluate quantitative changes of blood and lymphatic microcirculatory beds in cutaneous lichen planus (CLP) and psoriatic lesions using immunohistochemical analysis with antibodies to CD34, D2-40 and VEGF. Morphometric software was used to determine the area of blood and lymphatic vessels (BVA and LVA) and also the VEGF positive area. Statistical analysis of these parameters confirmed a significant enlargement of both the blood and lymphatic microcirculatory beds in psoriatic and CLP lesions. BVA in CLP lesions was increased by 56% however this augmentation was not as great as in psoriatic lesions where BVA was increased by 123%. Interestingly, LVA in psoriatic and CLP lesions was increased equally by 85%. The strongest VEGF expression was detected in psoriatic lesions, with lower, but still significant, overexpression in CLP lesions. VEGF-C was significantly increased in both psoriatic and CLP lesions in comparable level. Noticeably higher VEGF and VEGF-C expression was observed in the epidermis than in the dermis. Finally, our results indicate that the level of angiogenesis is considerably greater in psoriatic lesions than in CLP lesions, but the level of lymphangiogenesis is equal in both psoriatic and CLP lesions.

Study of in vitro capillary-like structures in psoriatic skin substitutes

Angiogenesis is one of the important hallmarks of psoriasis. The extension of the superficial microvascular structure and activated pro-angiogenic mediators in psoriasis seem to be important factors involved in the pathology. According to the changes of superficial microvasculature in psoriatic lesions, anti-angiogenic treatment could be a promising therapeutic strategy for psoriasis. The aim of this study was to construct an in vitro vascularized psoriatic skin substitute for fundamental research. Psoriatic fibroblasts and keratinocytes were isolated from psoriatic plaque biopsies, while healthy fibroblasts and keratinocytes, as well as microvascular endothelial cells, were isolated from healthy skin biopsies of cosmetic breast surgery. Psoriatic and healthy skin substitutes with and without endothelial cells were produced using the self-assembly approach. Afterward the substitutes were examined by histology, immunofluorescence studies, and three-dimensional (3D) confocal microscopy. Histological analysis and immunofluorescence staining of specific markers for endothelial cells (von Willebrand, PECAM-1 [CD31], and VE-cadherin [CD144]) and basement membrane component (collagen IV) demonstrated that endothelial cells have the ability to form capillary-like tubes. Moreover, the 3D branched structure of the capillary-like structures and an eagle eye view of them were observed by confocal microscopy. Also the semiquantification of capillary-like tubes (CLTs) was carried out with a 3D eagle eye view of substitutes, and more CLTs were observed in psoriatic substitutes. These results suggest that it is possible to observe 3D capillary-like structures in the self-assembled psoriatic skin substitutes, which could become a good in vitro testing model for anti-angiogenic drug research, and facilitate the study of this complex pathology, which links angiogenesis to its development.

CARD14 expression in dermal endothelial cells in psoriasis

Mutations in the caspase recruitment domain, family member 14 (CARD14) gene have recently been described in psoriasis patients, and explain the psoriasis susceptibility locus 2 (PSORS2). CARD14 is a scaffolding protein that regulates NF-κB activation, and psoriasis-associated CARD14 mutations lead to enhanced NF-κB signaling. CARD14 is expressed mainly in epidermal keratinocytes, but also in unidentified dermal cells. In this manuscript, the identity of the dermal cell types expressing CARD14, as well the potential functional consequence of overactive CARD14 in these dermal cell types, was determined. Using two-color immunofluorescence, dermal CARD14 did not co-localize with T-cells, dendritic cells, or macrophages. However, dermal CARD14 did highly co-localize with CD31⁺ endothelial cells (ECs). CARD14 was also expressed non-dermal endothelial cells, such as aortic endothelial cells, which may indicate a role of CARD14⁺ECs in the systemic inflammation and cardiovascular comorbidities associated with psoriasis. Additionally, phosphorylated NF-κB was found in psoriatic CARD14⁺ CD31⁺ ECs, demonstrating this pathway is active in dermal ECs in psoriasis. Transfection of dermal ECs with psoriasis-associated CARD14 mutations resulted in increased expression of several chemokines, including CXCL10, IL-8, and CCL2. These results provide preliminary evidence that CARD14 expression in ECs may contribute to psoriasis through increased expression of chemokines and facilitating recruitment of immune cells into skin.

In silico discovery of potential VEGFR-2 inhibitors from natural derivatives for anti-angiogenesis therapy

Angiogenesis is the growth of new capillaries from existing blood vessels that supply oxygen and nutrients and provide gateways for immune surveillance. Abnormal vessel growth in term of excessive angiogenesis is a hallmark of cancer, inflammatory and eye diseases. VEGFR-2 (vascular endothelial growth factor receptor 2) dominating the process of angiogenesis has led to approval of therapeutic inhibitors and is becoming a promising target for anti-angiogenic drugs. Notwithstanding these successes, the clinical use of current VEGFR-2 blockers is more challenging than anticipated. Taking axitinib as a reference drug, in our study we found three potent VEGFR-2 inhibitors (ZINC08254217, ZINC08254138, and ZINC03838680) from natural derivatives. Each of the three inhibitors acquired a better grid score than axitinib (−62.11) when docked to VEGFR-2. Molecular dynamics simulations demonstrated that ZINC08254217– and ZINC08254138–VEGFR-2 complexes were more stable than axitinib. Similar to bind free energy for axitinib (−54.68 kcal/mol), such for ZINC03838680, ZINC08254217, and ZINC08254138 was −49.37, −43.32, and −32.73 kcal/mol respectively. These results suggested these three compounds could be candidate drugs against angiogenesis, with comparable VEGFR-2 binding affinity of axitinib. Hence findings in our study are able to provide valuable information on discovery of effective anti-angiogenesis therapy.

Serum YKL-40 in psoriasis with and without arthritis; correlation with disease activity and high-resolution power Doppler ultrasonographic joint findings

BACKGROUND

YKL-40 may be involved in angiogenesis in psoriasis and psoriatic arthritis (PsA). High-resolution power Doppler ultrasound (PDUS) can detect angiogenesis of synovium in PsA.

AIM

To assess serum YKL-40 in psoriasis patients with or without PsA, and to correlate its levels with disease activity and high-resolution PDUS findings.

METHODS

In this case-control study, 48 patients with psoriasis (26 of them also had PsA) and 30 controls were assessed by high-resolution PDUS, and assayed for serum levels of YKL-40 by ELISA. Patients were clinically assessed using Composite Psoriatic Disease Activity Index (CPDAI). Total joint score (TJS) was used to assess joint involvement in PsA.

RESULTS

A statistically significant elevation was found in YKL-40 levels in psoriatics with or without PsA compared with controls (P < 0.001), as well as in PsA (group II) compared to patients without arthritis (group I) (P = 0.002). CPDAI, synovial thickness score and colour Doppler ultrasound (CDUS) score were highly significantly higher in group II vs. group I (P < 0.001). In all patients, CPDAI, synovial thickness and CDUS score were positively correlated to each other, and each of them was positively correlated to serum YKL-40 levels (P < 0.05). In either group I or II, serum YKL-40 levels correlated positively with CPDAI (P < 0.05). In group II, TJS, synovial thickness and CDUS score were positively correlated to each other (P < 0.05).

CONCLUSIONS

Serum YKL-40 can be used as a new biological marker for angiogenesis and disease activity in psoriasis with or without PsA. High-resolution PDUS is a non-invasive tool for the evaluation of angiogenesis in PsA patients as well as for the detection of early synovial changes in psoriasis patients without arthritis.

Cellular dissection of psoriasis for transcriptome analyses and the post-GWAS era

Background

Genome-scale studies of psoriasis have been used to identify genes of potential relevance to disease mechanisms. For many identified genes, however, the cell type mediating disease activity is uncertain, which has limited our ability to design gene functional studies based on genomic findings.

Methods

We identified differentially expressed genes (DEGs) with altered expression in psoriasis lesions (n = 216 patients), as well as candidate genes near susceptibility loci from psoriasis GWAS studies. These gene sets were characterized based upon their expression across 10 cell types present in psoriasis lesions. Susceptibility-associated variation at intergenic (non-coding) loci was evaluated to identify sites of allele-specific transcription factor binding.

Results

Half of DEGs showed highest expression in skin cells, although the dominant cell type differed between psoriasis-increased DEGs (keratinocytes, 35%) and psoriasis-decreased DEGs (fibroblasts, 33%). In contrast, psoriasis GWAS candidates tended to have highest expression in immune cells (71%), with a significant fraction showing maximal expression in neutrophils (24%, P < 0.001). By identifying candidate cell types for genes near susceptibility loci, we could identify and prioritize SNPs at which susceptibility variants are predicted to influence transcription factor binding. This led to the identification of potentially causal (non-coding) SNPs for which susceptibility variants influence binding of AP-1, NF-κB, IRF1, STAT3 and STAT4.

Conclusions

These findings underscore the role of innate immunity in psoriasis and highlight neutrophils as a cell type linked with pathogenetic mechanisms. Assignment of candidate cell types to genes emerging from GWAS studies provides a first step towards functional analysis, and we have proposed an approach for generating hypotheses to explain GWAS hits at intergenic loci.

Inositoylated platelet-activating factor (Ino-C2-PAF) modulates dynamic lymphocyte-endothelial cell interactions and alleviates psoriasis-like skin inflammation in two complementary mouse models

Psoriasis, a tumor necrosis factor alpha (TNFα)-governed inflammatory disorder with prominent dysregulation of cutaneous vascular functions, has evolved into a model disorder for studying anti-inflammatory therapies. We present experimental in vitro and in vivo data on 1-O-octadecyl-2-O-(2-(myo-inositolyl)-ethyl)-sn-glycero-3-(R/S)-phosphatidyl-choline (Ino-C2-PAF), the lead compound of a class of synthetic glycosylated phospholipids, in anti-inflammatory therapy. Ino-C2-PAF strongly induced apoptosis only in TNFα-stimulated, but not in untreated human vascular endothelial cells. Moreover, TNFα-induced endothelial adhesion molecules that mediated the rolling and firm adhesion of leukocytes (vascular cell adhesion protein-1 (VCAM-1), E-selectin, and ICAM-1) were selectively downregulated by Ino-C2-PAF. Similarly, expression of L-selectin, VCAM-1 receptor α4β1 integrin , and lymphocyte function-associated antigen-1 on human peripheral blood mononuclear cells was reduced without induction of apoptosis. Functionally, these changes were accompanied by significant impairment of rolling and adhesion of human peripheral blood lymphocytes on TNFα-activated endothelial cells in a dynamic flow chamber system. When the therapeutic potential of Ino-C2-PAF was assessed in two complementary mouse models of psoriasis, K5.hTGFβ1 transgenic and JunB/c-Jun-deficient mice, Ino-C2-PAF led to significant alleviation of the clinical symptoms and normalized the pathological cutaneous changes including vascularization. There were no overt adverse effects. These findings suggested that Ino-C2-PAF is a potential candidate in the therapy of inflammatory skin diseases that include abnormal vascular functions.

The antiangiogenic insulin receptor substrate-1 antisense oligonucleotide aganirsen impairs AU-rich mRNA stability by reducing 14-3-3β-tristetraprolin protein complex, reducing inflammation and psoriatic lesion size in patients

Increased inflammation and aberrant angiogenesis underlie psoriasis. Here, we report that the inhibition of insulin receptor substrate-1 (IRS-1) expression with aganirsen resulted in a dose-dependent reduction (P < 0.0001) in IRS-1 protein in the cytoplasm, while IRS-1 protein remained quantitatively unchanged in the perinuclear environment. Aganirsen induced a dose-dependent increase in serine-phosphorylated IRS-1 in the soluble perinuclear-nuclear fraction, inducing IRS-1-14-3-3β protein association (P < 0.001), thereby impairing 14-3-3β-tristetraprolin protein complex and AU-rich mRNA's stability (P < 0.001). Accordingly, aganirsen inhibited (P < 0.001) in vitro the expression of interleukin-8 (IL-8), IL-12, IL-22, and tumor necrosis factor alpha (TNFα), four inflammatory mediators containing mRNA with AU-rich regions. To demonstrate the clinical relevance of this pathway, we tested the efficacy of aganirsen by topical application in a pilot, double-blind, randomized, dose-ranging study in 12 psoriatic human patients. After 6 weeks of treatment, least square mean differences with placebo were -38.9% (95% confidence interval, -75.8 to -2.0%) and -37.4% (-74.3 to -0.5%) at the doses of 0.86 and 1.72 mg/g, respectively. Lesion size reduction was associated with reduced expression of IRS-1 (P < 0.01), TNFα (P < 0.0001), and vascular endothelial growth factor (P < 0.01); reduced keratinocyte proliferation (P < 0.01); and the restoration (P < 0.02) of normal levels of infiltrating CD4(+) and CD3(+) lymphocytes in psoriatic skin lesions. These results suggest that aganirsen is a first-in-class of a new generation of antiangiogenic medicines combining anti-inflammatory activities. Aganirsen-induced downregulation of inflammatory mediators characterized by AU-rich mRNA likely underlies its beneficial clinical outcome in psoriasis. These results justify further large-scale clinical studies to establish the dose of aganirsen and its long-term efficacy in psoriasis.