CCL7 contributes to the TNF‐alpha‐dependent inflammation of lesional psoriatic skin

Chemokines are small chemotactic proteins that have a crucial role in leukocyte recruitment into tissue. Targeting these mediators has been suggested as a potential therapeutic option in inflammatory skin diseases such as psoriasis. Using quantitative RT‐PCR, we found CCL7, a chemokine ligand known to interact with multiple C‐C chemokine receptors, to be markedly increased in lesional psoriasis as opposed to atopic dermatitis, lichen planus, non‐lesional psoriatic and normal control skin. Surprisingly, this increase in CCL7 mRNA expression exceeded that of all other chemokines investigated, and keratinocytes and dermal blood endothelial cells were identified as its likely cellular sources. In an imiquimod‐induced psoriasis‐like mouse model, CCL7 had a profound impact on myeloid cell inflammation as well as on the upregulation of key pro‐psoriatic cytokines such as CCL20, IL‐12p40 and IL‐17C, while its blockade led to an increase in the antipsoriatic cytokine IL‐4. In humans receiving the TNF‐α‐blocker infliximab, CCL7 was downregulated in lesional psoriatic skin already within 16 hours after a single intravenous infusion. These data suggest that CCL7 acts as a driver of TNF‐α‐dependent Th1/Th17‐mediated inflammation in lesional psoriatic skin.     

Circulating adipokine levels in Portuguese patients with psoriasis vulgaris according to body mass index,severity and therapy

Background Psoriasis vulgaris is associated with overweight/obesity and with increased C‐reactive protein (CRP), tumour necrosis factor (TNF)‐α, interleukin (IL)‐6, leptin and resistin levels and decreased adiponectin levels. Objectives To understand the role/relationship of adipokines, as well as CRP, in a Portuguese psoriatic population, by assessing the relationship of their levels with psoriasis severity, defined by Psoriasis Area and Severity Index (PASI), with obesity, defined by body mass index (BMI), and psoriasis therapy. Methods A cross‐sectional (n = 66) and longitudinal study (before and after 12 weeks of therapy; n = 44) was performed; 10 patients started topical treatment, 17 narrow‐band ultraviolet B (NBUVB) and 17 psolaren associated with UVA (PUVA). Results Patients presented significantly higher BMI, leptin, resistin, TNF‐α, IL‐6 and CRP and significantly lower adiponectin values. CRP and IL‐6 correlated with PASI. Adiponectin and leptin were more altered in patients with higher BMI. Concerning severity, CRP, resistin and adiponectin were more altered in the severer forms. After treatment, a significant reduction in PASI, CRP, resistin, TNF‐α and IL‐6, and a significant rise in adiponectin were observed. Nonetheless, CRP and adiponectin remained different from those of control. Concerning therapies, topical therapy was not associated with any significant change, except for TNF‐α. After NBUVB, a significant reduction was observed in TNF‐α and in CRP. For PUVA, we observed a significant reduction in TNF‐α, IL‐6 and CRP, and a significant increase in adiponectin. Conclusion In psoriatic patients, increased overweight/obesity was associated with raised leptin levels and decreased adiponectin levels. Leptin may contribute to enhance the inflammatory process in overweight/obese psoriatic patients. Resistin, IL‐6, CRP and adiponectin levels appear to be dependent on psoriasis severity. CRP, together with IL‐6, appears to be a useful marker of psoriasis severity. Both NBUVB and PUVA were effective; however, PUVA results seem to be more successful. Nonetheless, after NBUVB and PUVA, a low‐grade inflammation still persists.     

RNA, DNA, and cell surface characteristics of lesional and nonlesional psoriatic skin

We have measured the RNA and DNA content and examined cell surface characteristics of human epidermal cells derived from normal skin, and lesional and nonlesional areas of psoriatic skin prior to and following treatment on a modified Goeckerman protocol. Our results show that cells from active psoriatic lesions contain greater numbers of basal keratinocytes when compared with either nonlesional skin from the same patients or skin from healthy volunteers and individuals with other inflammatory skin lesions. Follow-up measurements 2-3 weeks after the initiation of therapy showed that the numbers of basal keratinocytes in resolving psoriatic lesions had decreased and approached normal levels. Multiparameter RNA/DNA flow cytometric analysis on parallel samples from the same psoriasis patients revealed an increased growth fraction and proportion of cycling cells in both the nonlesional and lesional skin compared with controls. Furthermore, the cellular RNA content was elevated in lesional psoriatic skin when compared with either nonlesional or normal skin. Flow cytometric examination of nonlesional and lesional epidermal cells obtained 2-3 weeks after the commencement of therapy revealed that the growth fraction and mean RNA content of the keratinocytes from resolving psoriatic plaques decreased in response to therapy. In contrast, the proportion of keratinocytes within the S + G2 + M phases of the cell cycle remained elevated. These data indicate that "uninvolved" psoriatic skin exhibits characteristics more closely resembling lesional psoriatic skin than normal skin. The results further suggest that quantitation of cellular RNA content and basal cell number might be sensitive indicators of early treatment response in psoriasis.     

Insulin‐like growth factor‐1 in psoriatic plaques treated with PUVA and methotrexate

Background The pathogenesis of psoriasis is thought to depend on the activation of immune cells and their secreted cytokines, chemokines and growth factors like IGF‐1 which may contribute to the epidermal hyperplasia of psoriasis. Treatment of psoriasis with PUVA and methotrexate are associated with clinical improvement and decrease in epidermal hyperplasia. Objective To examine the effects of PUVA and methotrexate therapy on IGF‐1 expression in psoriatic plaques and whether this change correlates with clinical response. Methods For 24 psoriatic patients, the PASI score and levels of lesional IGF‐1 and its mRNA were determined by RT‐PCR before and after treatment with either methotrexate or PUVA. Skin biopsies from 12 healthy volunteers served as control for IGF‐1 levels in normal skin. Results Lesional skin of psoriatic patients showed a statistically significant elevation in IGF‐1 and its mRNA levels in comparison to control (P = 0.0001). Both methotrexate and PUVA treatment were associated with a significant decrease in both PASI scores and lesional IGF‐1 after 10 month treatment. Conclusion Both methotrexate and PUVA therapy for psoriasis are associated with a decrease in PASI score and IGF‐1. The IGF‐1 down‐regulation may possibly be a consequence of the decrease in cytokines and inflammatory cellular infiltrate that occur following treatment with either modalities or due to their effect on local fibroblast activity and proliferation.     

The role of IL‐23 and the IL‐23/TH17 immune axis in the pathogenesis and treatment of psoriasis

Psoriasis is a chronic, immune‐mediated disease affecting more than 100 million people worldwide and up to 2.2% of the UK population. The aetiology of psoriasis is thought to originate from an interplay of genetic, environmental, infectious and lifestyle factors. The manner in which genetic and environmental factors interact to contribute to the molecular disease mechanisms has remained elusive. However, the interleukin 23 (IL‐23)/T‐helper 17 (T_H17) immune axis has been identified as a major immune pathway in psoriasis disease pathogenesis. Central to this pathway is the cytokine IL‐23, a heterodimer composed of a p40 subunit also found in IL‐12 and a p19 subunit exclusive to IL‐23. IL‐23 is important for maintaining T_H17 responses, and levels of IL‐23 are elevated in psoriatic skin compared with non‐lesional skin. A number of agents that specifically inhibit IL‐23p19 are currently in development for the treatment of moderate‐to‐severe plaque psoriasis, with recent clinical trials demonstrating efficacy with a good safety and tolerability profile. These data support the role of this cytokine in the pathogenesis of psoriasis. A better understanding of the IL‐23/T_H17 immune axis is vital and will promote the development of additional targets for psoriasis and other inflammatory diseases that share similar genetic aetiology and pathogenetic pathways.     

Infliximab restores the balance between pro- and anti-apoptotic proteins in regressing psoriatic lesions

Background Psoriasis and psoriatic arthritis are treated very efficaciously with infliximab, a chimaeric human–murine antitumour necrosis factor (TNF)‐α antibody. As we reported earlier, infliximab, besides its anti‐inflammatory properties, induces a caspase‐independent programmed cell death of psoriatic keratinocytes. Objectives To elucidate this finding further, we investigated the epidermal expression of proteins involved in the mitochondria‐dependent (intrinsic) pathway of cell death. Methods Quantification of proteins with pro‐ (p53, AIF, Bax) and anti‐apoptotic functions (Bcl‐2, Bcl‐XL) and of NF‐κB was performed by means of immunohistochemistry and digital image analysis of the staining of nonlesional skin and lesional psoriatic skin from patients treated with infliximab at weeks 0, 2 and 6. Results Serial biopsies from psoriatic plaques of samples taken at days 0, 5, 14 and 21 of therapy demonstrated a significant downregulation of anti‐apoptotic proteins Bcl‐2, Bcl‐XL and NF‐κB during treatment and, in parallel, a significant upregulation of pro‐apoptotic proteins p53, Bax and AIF. These differences in expression correlated with decreases in epidermal thickness and clinical outcome (Psoriasis Area and Severity Index). At day 21, expression levels of apoptosis‐related proteins in lesional skin approximated those found in nonlesional skin. Conclusions Our data therefore suggest that TNF‐targeting agents may induce the regression of psoriasis at least in part by normalizing the expression of apoptosis‐related proteins in lesional keratinocytes.     

Sebocytes differentially express and secrete adipokines

In addition to producing sebum, sebocytes link lipid metabolism with inflammation at a cellular level and hence, greatly resemble adipocytes. However, so far no analysis was performed to identify and characterize the adipocyte‐associated inflammatory proteins, the members of the adipokine family in sebocytes. Therefore, we determined the expression profile of adipokines [adiponectin, interleukin (IL) 6, resistin, leptin, serpin E1, visfatin, apelin, chemerin, retinol‐binding protein 4 (RBP4) and monocyte chemoattractant protein 1 (MCP1)] in sebaceous glands of healthy and various disease‐affected (acne, rosacea, melanoma and psoriasis) skin samples. Sebaceous glands in all examined samples expressed adiponectin, IL6, resistin, leptin, serpin E1 and visfatin, but not apelin, chemerin, RBP4 and MCP1. Confirming the presence of the detected adipokines in the human SZ95 sebaceous gland cell line we further characterized their expression and secretion patterns under different stimuli mimicking bacterial invasion [by using Toll‐like receptor (TLR)2 and 4 activators], or by 13‐cis retinoic acid (13CRA; also known as isotretinoin), a key anti‐acne agent. With the exception of resistin, the expression of all of the detected adipokines (adiponectin, IL6, leptin, serpin E1 and visfatin) could be further regulated at the level of gene expression, showing a close correlation with the secreted protein levels. Besides providing further evidence on similarities between adipocytes and sebocytes, our results strongly suggest that sebocytes are not simply targets of inflammation but may exhibit initiatory and modulatory roles in the inflammatory processes of the skin through the expression and secretion of adipokines.     

Interleukin 1 alpha and beta in psoriatic skin: enzymoimmunoassay, immunoblot studies and effect of systemic retinoids

Interleukin 1 alpha (IL-1 alpha) and interleukin 1 beta (IL-1 beta) proteins were studied by enzymoimmunoassay (EIA) and Immunoblot analysis in the 10,000 g supernatant of normal and psoriatic (lesional and nonlesional) human skin specimens. By EIA IL-1 alpha was the principal form detected in all the specimens, which contrasts with the predominance of IL-1 beta in human blood monocytes. In psoriatic plaques relatively less IL-1 alpha and more IL-1 beta were detected. On Immunoblot analysis the mature form (17 kD) was not detected in normal skin, which showed only 52-kD immunoreactive forms. In contrast the 17-kD form was found in psoriatic skin. This indicates either a distinct processing of IL-1 molecules or a contribution of inflammatory cells infiltration to the IL-1 pool in psoriatic plaques. During systemic retinoids therapy the amount of both IL-1 species decreased in lesional and nonlesional psoriatic skin.     

Estimation of tissue osteopontin levels before and after different traditional therapeutic modalities in psoriatic patients

Background Several lines of evidences support a major role for Th1 cells in psoriasis. Treatment of psoriasis with cyclosporine, methotrexate and psoralen plus ultraviolet A (PUVA) is associated with clinical improvement and decrease in epidermal hyperplasia. Osteopontin (OPN) exerts a T‐helper type 1 (Th1) cytokine function, regulating inflammatory cell accumulation and function. Objective To detect the effects of methotrexate, cyclosporine and PUVA on OPN expression in psoriatic plaques, and whether these changes correlate with clinical response. Methods For three groups of psoriatic patients (each including 12 patients), the Psoriasis Area Severity Index (PASI) and levels of lesional skin OPN were determined using enzyme‐linked immunosorbent assays before and after treatment with methotrexate, cyclosporine or PUVA. Skin biopsies from 20 healthy volunteers served as control for OPN levels in normal skin. Results Baseline lesional skin of psoriatic patients showed a statistically significant elevation of OPN levels in comparison to controls. Three months after therapy, the three therapeutic modalities were associated with a significant decrease in the mean levels of PASI and tissue OPN, with the PUVA group showing the highest level of reduction in OPN levels and cyclosporine group showing the highest level of reduction in PASI. Conclusion Our study points to the possible role played by OPN in the pathogenesis of psoriasis and in reflecting disease severity. These standard therapeutic modalities used in the current study were associated with a significant decrease in PASI and OPN levels. They constitute highly effective therapeutic modalities for psoriasis, which might exert their anti‐psoriatic activity partially through altering the expression of OPN.     

Mast cell density and IL-8 expression in nonlesional and lesional psoriatic skin

BACKGROUND: An important cellular aberration at sites of psoriatic inflammation is an increase in the number of dermal mast cells. Being multifactorial immune effector cells, it is believed that mast cells play an essential role in perpetuating the inflammatory process of psoriasis. However, factors responsible for the infiltration and accumulation of mast cells in psoriatic lesions are largely unknown. Recent studies have demonstrated that Interleukin-8 (IL-8) exerts strong chemotactic effects on mast cells in vitro. Overexpression of IL-8 has also been reported in psoriatic lesions. In this study, we have found a correlation between the expression of IL-8 and dermal mast cell density in lesional psoriatic skin as compared to nonlesional psoriatic skin. METHODS: Four-mm punch biopsies were taken from 14 psoriatic patients and eight healthy volunteers. Using immunohistochemical techniques, 8 microm sections of lesional psoriatic, nonlesional psoriatic, and normal control samples were evaluated for dermal mast cell density and the density of IL-8 expressing keratinocytes. RESULTS: It was found that dermal mast cell density in lesional psoriatic, nonlesional psoriatic, and normal skin was 105.4 +/- 71.2, 42.3 +/- 30.1, and 47.5 +/- 32.5 mast cells/mm(2), respectively. IL-8+ keratinocyte density in lesional psoriatic, non lesional psoriatic, and normal skin was 171.5 +/- 67.1, 25.4 +/- 14.9 and 20.6 +/- 8.7 IL-8+ Keratinocytes/mm(2), respectively. CONCLUSIONS: The results of this study suggest that increased levels of IL-8 in the keratinocytes of psoriatic plaques play a contributing role in the migration of mast cells to lesion sites.     

Biomarkers of alopecia areata disease activity and response to corticosteroid treatment

Alopecia areata (AA) is a common inflammatory disease targeting the anagen‐stage hair follicle. Different cytokines have been implicated in the disease profile, but their pathogenic role is not yet fully determined. We studied biopsies of pretreatment lesional and non‐lesional (NL) scalp and post‐treatment (intra‐lesional steroid injection) lesional scalp of 6 patchy patients with AA using immunohistochemistry and gene expression analysis. Immunohistochemistry showed increases in CD3⁺, CD8⁺ T cells, CD11c⁺ dendritic cells and CD1a⁺ Langerhans cells within and around hair follicles of pretreatment lesional scalp, which decreased upon treatment. qRT‐PCR showed in pretreatment lesional scalp (compared to NL) significant increases (P < 0.05) in expression of inflammatory markers (IL‐2, IL‐2RA, JAK3, IL‐15), Th1 (CXCL10 and CXCL9), Th2 (IL‐13, CCL17 and CCL18), IL‐12/IL‐23p40 and IL‐32. Among these, we observed significant downregulation with treatment in IL‐12/IL‐23p40, CCL18 and IL‐32. We also observed significant downregulation of several hair keratins in lesional scalp, with significant upregulation of KRT35, KRT75 and KRT86 in post‐treatment lesional scalp. This study shows concurrent activation of Th1 and Th2 immune axes as well as IL‐23 and IL‐32 cytokine pathways in lesional AA scalp and defined a series of response biomarkers to corticosteroid injection. Clinical trials with selective antagonists coupled with cytokine‐pathway biomarkers will be necessary to further dissect pathogenic immunity.     

Prolactin level is significantly elevated in lesional skin of patients with psoriasis

Background Accumulating data point to a potential role of prolactin in the pathogenesis of psoriasis. Methods We initiated a study including psoriasis patients (n = 15) and healthy volunteers (n = 15) as controls. Psoriasis area and severity index (PASI) score was evaluated, and prolactin levels in serum and blister fluid were assessed by enzyme‐linked immunosorbent assay (ELISA). Results Prolactin levels were significantly (P < 0.01) elevated in blister fluid of psoriatic lesional skin. Correlations between PASI score and different serum prolactin levels in lesional and non‐lesional skin were insignificant. Significant positive correlations of prolactin level were observed between lesional and non‐lesional skin in psoriasis (P < 0.05) and between serum and clinically normal skin in both psoriasis and control subjects (P < 0.05). Conclusions Locally produced prolactin may be involved in the pathogenesis of psoriatic lesions.     

Mast cell density in psoriatic skin. The effect of PUVA and corticosteroid therapy

Summary Numbers and volume fractions of mast cells in nonlesional and chronic lesional skin of psoriatic patients were compared with those of normal control skin. Mast cell densities were similar in psoriatic nonlesional and normal control skin. The superficial dermis of lesional psoriatic skin contained more mast cells than either normal or nonlesional psoriatic skin. Neither PUVA nor corticosteroid treatment for 3–4 weeks significantly reduced mast cell numbers or volume fractions in lesional skin, although both treatments clinically and histologically markedly improved the lesions. The results indicate that the initiation of the healing process in psoriatic plaques is not correlated with the mast cell density. The remaining high mast cell density may be normalized later, or after a longer therapy.     

The anti‐apoptotic protein G1P3 is overexpressed in psoriasis and regulated by the non‐coding RNA,PRINS

Please cite this paper as: The anti‐apoptotic protein G1P3 is overexpressed in psoriasis and regulated by the non‐coding RNA, PRINS. Experimental Dermatology 2010; 19: 269–278. Abstract: Psoriasis Susceptibility‐Related RNA Gene Induced by Stress (PRINS) is a non‐coding RNA overexpressed in lesional and non‐lesional psoriatic epidermis and induced by stress. Its function in healthy and psoriatic skin is still not known. Here, we report that PRINS regulates G1P3, a gene with anti‐apoptotic effects in keratinocytes. siRNA‐mediated inhibition of PRINS gene resulted in altered cell morphology and gene expression alterations, as demonstrated in a microarray experiment. One of the genes regulated by PRINS ncRNA was G1P3, an interferon‐inducible gene with anti‐apoptotic effects in cancer cells. Interestingly, we found that G1P3 was 400‐fold upregulated in hyperproliferative lesional and ninefold upregulated in non‐lesional psoriatic epidermis compared to healthy epidermis. In vitro, G1P3 protein levels were highest in proliferating keratinocytes and siRNA‐mediated downregulation of G1P3 resulted in increased cell apoptosis. These data indicate that G1P3 inhibits spontaneous keratinocyte apoptosis and hence its high expression in psoriatic skin may contribute to the development of psoriatic lesions. We hypothesize that the deregulation of the PRINS ncRNA may contribute to psoriasis and results in decreased sensitivity to spontaneous keratinocyte apoptosis via the regulation of G1P3.     

Elevated transglutaminase‐2 expression in the epidermis of psoriatic skin and its role in the skin lesion development

Psoriasis, an inflammatory skin disease triggered by the immune system, presents keratinocyte hyperproliferation, differentiation and angiogenesis. The role of transglutaminase‐2 (TG2) in psoriasis has not been fully established yet. In this retrospective, non‐randomized and non‐blinded study, skin biopsies were collected from 37 psoriatic patients and immunohistochemical staining was performed. TG2 staining was positive in all 37 samples, among which 32 were strong and five weak. The localization of TG2 staining was present in the epidermis and spreading from basal layer to stratum granulosum in decreasing staining intensity. However, TG2 was also expressed in the basal layer in the non‐lesional site of psoriasis and the skin of healthy people. The presence of TG2 was not associated with disease duration, stage of disease and subtype of psoriasis. Overexpression of TG2 seems to be an important role in psoriatic development.