Alteration of the expression of Bcl-2, Bcl-x, Bax, Fas, and Fas ligand in the involved skin of psoriasis vulgaris following topical anthralin therapy

Investigation on the Mechanism of Qubi Formula in Treating Psoriasis Based on Network Pharmacology

Objective

To elucidate the pharmacological mechanisms of Qubi Formula (QBF), a traditional Chinese medicine (TCM) formula which has been demonstrated as an effective therapy for psoriasis in China.

Methods

The Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, BATMAN-TCM database, and literature search were used to excavate the pharmacologically active ingredients of QBF and to predict the potential targets. Psoriasis-related targets were obtained from Therapeutic Target Database (TTD), DrugBank database (DBD), MalaCards database, and DisGeNET database. Then, we established the network concerning the interactions of potential targets of QBF with well-known psoriasis-related targets by using protein-protein interaction (PPI) data in String database. Afterwards, topological parameters (including DNMC, Degree, Closeness, and Betweenness) were calculated to excavate the core targets of Qubi Formula in treating psoriasis (main targets in the PPI network). Cytoscape was used to construct the ingredients-targets core network for Qubi Formula in treating psoriasis, and ClueGO was used to perform GO-BP and KEGG pathway enrichment analysis on these core targets.

Results

The ingredient-target-disease core network of QBF in treating psoriasis was screened to contain 175 active ingredients, which corresponded to 27 core targets. Additionally, enrichment analysis suggested that targets of QBF in treating psoriasis were mainly clustered into multiple biological processes (associated with nuclear translocation of proteins, cellular response to multiple stimuli (immunoinflammatory factors, oxidative stress, and nutrient substance), lymphocyte activation, regulation of cyclase activity, cell-cell adhesion, and cell death) and related pathways (VEGF, JAK-STAT, TLRs, NF-κB, and lymphocyte differentiation-related pathways), indicating the underlying mechanisms of QBF on psoriasis.

Conclusion

In this work, we have successfully illuminated that Qubi Formula could relieve a wide variety of pathological factors (such as inflammatory infiltration and abnormal angiogenesis) of psoriasis in a "multicompound, multitarget, and multipathway" manner by using network pharmacology. Moreover, our present outcomes might shed light on the further clinical application of QBF on psoriasis treatment.

Dithranol: An Insight into its Novel Delivery Cargos for Psoriasis Management

OBJECTIVE

Dithranol (DTH) is a well-known moiety that has long been used promisingly to impede and treat skin disorders, particularly psoriasis. Nowadays, a rekindled interest in the use of DTH for this disorder has been observed. Side effects associated with conventional topical formulations of this moiety have aroused the interest of the scientific community in investigating novel cargos of DTH for psoriasis management.

RESULTS

Previous research has evidenced the anti-inflammatory and anti-proliferating potential of DTH. Numerous studies have indicated that DTH inhibits polymorphonuclear (PMN) leucocyte, modulates epidermal cell receptors and promotes anti-psoriatic action. However, some deterrent factors like poor solubility, stability, toxicity, staining and skin irritation hamper its use as a potential therapeutic agent. With the adoption of novel drug delivery technologies, the above mentioned inherent limitations of DTH have been compensated to reestablish this drug moiety.

CONCLUSION

This article reviews novel drug delivery aspects, safety concerns, clinical evidence, current status, and future opportunities of DTH in the management of psoriasis. Further, it will update researchers on this promising drug moiety, which is free from systemic adverse responses in comparison to other therapeutic molecules like steroids, for psoriasis treatment.

Dithranol targets keratinocytes, their crosstalk with neutrophils and inhibits the IL-36 inflammatory loop in psoriasis

Despite the introduction of biologics, topical dithranol (anthralin) has remained one of the most effective anti-psoriatic agents. Serial biopsies from human psoriatic lesions and both the c-Jun/JunB and imiquimod psoriasis mouse model allowed us to study the therapeutic mechanism of this drug. Top differentially expressed genes in the early response to dithranol belonged to keratinocyte and epidermal differentiation pathways and IL-1 family members (i.e. IL36RN) but not elements of the IL-17/IL-23 axis. In human psoriatic response to dithranol, rapid decrease in expression of keratinocyte differentiation regulators (e.g. involucrin, SERPINB7 and SERPINB13), antimicrobial peptides (e.g. ß-defensins like DEFB4A, DEFB4B, DEFB103A, S100 proteins like S100A7, S100A12), chemotactic factors for neutrophils (e.g. CXCL5, CXCL8) and neutrophilic infiltration was followed with much delay by reduction in T cell infiltration. Targeting keratinocytes rather than immune cells may be an alternative approach in particular for topical anti-psoriatic treatment, an area with high need for new drugs.

Dithranol treatment of plaque-type psoriasis increases serum TNF-like weak inducer of apoptosis (TWEAK)

PURPOSE

TNF-like weak inducer of apoptosis (TWEAK) mediates not only apoptosis, but also inflammation, cell growth and angiogenesis. The role of TWEAK in psoriasis remains unknown. The aim of the study was to assess serum levels of TWEAK in psoriatic patients before and after topical treatment with dithranol in relation to the clinical activity of the disease.

MATERIAL AND METHODS

Serum samples were collected from 40 patients with plaque type psoriasis before and after topical treatment with dithranol. The concentrations of serum TWEAK were measured by ELISA and next compared with 16 healthy controls. The data were analyzed with respect to Psoriasis Area and Severity Index (PASI).

RESULTS

Baseline serum TWEAK concentrations of psoriatic patients (685±166pg/ml) were significantly greater compared to healthy controls (565±110pg/ml). Topical treatment resulted in further increase in serum TWEAK (749±179pg/ml; p<0.01). In case of patients with initial serum TWEAK concentrations above the median, PASI after topical treatment was lower compared to the individuals with initial TWEAK below the median.

CONCLUSION

According to the study, serum Tweak was increased in psoriasis patients compared with controls. Moreover, dithranol topical treatment caused further increase in serum TWEAK. Also, a higher effectiveness of topical treatment was observed in case of patients with higher initial TWEAK concentrations. The results suggest a potential role of TWEAK in psoriasis therapy.

Biomarkers of An Autoimmune Skin Disease--Psoriasis

Psoriasis is one of the most prevalent autoimmune skin diseases. However, its etiology and pathogenesis are still unclear. Over the last decade, omics-based technologies have been extensively utilized for biomarker discovery. As a result, some promising markers for psoriasis have been identified at the genome, transcriptome, proteome, and metabolome level. These discoveries have provided new insights into the underlying molecular mechanisms and signaling pathways in psoriasis pathogenesis. More importantly, some of these markers may prove useful in the diagnosis of psoriasis and in the prediction of disease progression once they have been validated. In this review, we summarize the most recent findings in psoriasis biomarker discovery. In addition, we will discuss several emerging technologies and their potential for novel biomarker discovery and diagnostics for psoriasis.

In silico database screening of potential targets and pathways of compounds contained in plants used for psoriasis vulgaris

Reviews and meta-analyses of clinical trials identified plants used as traditional medicines (TMs) that show promise for psoriasis. These include Rehmannia glutinosa, Camptotheca acuminata, Indigo naturalis and Salvia miltiorrhiza. Compounds contained in these TMs have shown activities of relevance to psoriasis in experimental models. To further investigate the likely mechanisms of action of the multiple compounds in these TMs, we undertook a computer-based in silico investigation of the proteins known to be regulated by these compounds and their associated biological pathways. The proteins reportedly regulated by compounds in these four TMs were identified using the HIT (Herbal Ingredients' Targets) database. The resultant data were entered into the PANTHER (Protein ANnotation THrough Evolutionary Relationship) database to identify the pathways in which the proteins could be involved. The study identified 237 compounds in the TMs and these retrieved 287 proteins from HIT. These proteins identified 59 pathways in PANTHER with most proteins being located in the Apoptosis, Angiogenesis, Inflammation mediated by chemokine and cytokine, Gonadotropin releasing hormone receptor, and/or Interleukin signaling pathways. All four TMs contained compounds that had regulating effects on Apoptosis regulator BAX, Apoptosis regulator Bcl-2, Caspase-3, Tumor necrosis factor (TNF) or Prostaglandin G/H synthase 2 (COX2). The main proteins and pathways are primarily related to inflammation, proliferation and angiogenesis which are all processes involved in psoriasis. Experimental studies have reported that certain compounds from these TMs can regulate the expression of proteins involved in each of these pathways.

Upregulation of the sFas/sFasL system in psoriatic patients

PURPOSE

Psoriasis is a chronic, recurrent, inflammatory disease. Recent investigations indicate its autoimmune pathogenesis. Apoptosis plays an important role in the development of many autoimmune diseases. The aim of this study was to evaluate the influence of topical treatment of psoriasis on soluble Fas (sFas) and soluble Fas-ligand (sFasL).

MATERIAL/METHODS

Serum concentrations of sFas and sFasL were measured using ELISA in 40 psoriatic patients before and after topical treatment with dithranol and compared to the values obtained from 16 healthy subjects. Data were analyzed with respect to severity of psoriasis, duration of the disease and coexisting obesity, diabetes and hypertension.

RESULTS

We found that serum levels of sFas before (11.9±2.4ng/mL) and after treatment (12.2±2.5ng/mL) were significantly higher in patients with psoriasis as compared to the control group (6.4±1.8ng/mL). Concentrations of sFasL did not differ significantly from healthy subjects, but increased after treatment. The sFas/sFasL ratio was significantly higher in psoriasis (128±47) than in the control group and, even though it tended to decrease after treatment, it still remained higher than in the control group (65±22). Additionally we observed a positive correlation of sFas/sFasL ratio with the age of patients and duration of the disease. Psoriatic patients suffering from hypertension and overweight had significantly higher sFas/sFasL ratio than other psoriatic patients.

CONCLUSIONS

Our data indicate upregulation of the sFas/sFasL system in psoriatic patients. We demonstrate association of sFas/sFasL with commorbidities - components of metabolic syndrome.

Anthralin/dithranol in dermatology

Anthralin (1,8-dihydroxy-9anthrone, dithranol) was first synthesized as a derivative of chrysarobin, prepared from the araroba tree in Brazil over a century ago. Drawbacks to the use of anthralin include irritation and discoloration of the skin. This property of the molecule prompted workers to investigate details of its pharmacology, mode of action, and indications. The major point of this article is to highlight and revisit these aspects for pertinent future use. Therefore, it is worthwhile to consider that the drug is relatively innocuous, yet effective, and is devoid of any systemic side effects in contrast to a wide variety of systemic and topical therapies available for psoriasis and other dermatoses.

An investigation of the effects of dithranol-induced apoptosis in a human keratinocyte cell line

Objectives

Dithranol, one of the most successful topical agents for the treatment of psoriasis, has been shown to exert its therapeutic effect by inducing keratinocyte apoptosis. To gain further insights into dithranol-induced apoptotic events in vitro, a detailed investigation of its time- and dose-dependent effects has been performed through the evaluation of selected apoptotic markers, using a human keratinocyte cell line (HaCaT) as a model.

Methods

The time- and dose-dependent effects of dithranol on a human keratinocyte cell line (HaCaT) were investigated through the evaluation of a series of apoptotic markers; morphological changes (electron microscopy), phosphatidylserine externalisation (flow cytometry), and caspase-3/7 activation.

Key findings

The dithranol-induced apoptotic cascade was found to follow a well-defined dose and time-course, with the concentration and the period of exposure to the drug acting as the two major factors influencing the events and nature of cell death. The earliest apoptotic event detected was caspase activation (after 6 h), followed by the occurrence of phosphatidylserine externalisation (after 9 h) and subsequently the morphological characteristics associated with early and late stage apoptosis/necrosis (after 12 h).

Conclusions

This study has elucidated the dose- and time-response effects of dithranol-induced apoptosis in human keratinocytes in vitro.

Effects of the antipsoriatic drug dithranol on E2A and caspase-9 gene expression in vitro

Although the precise causes of psoriasis remain to be elucidated, psoriasis has been known as a disorder in which factors in the immune system, enzymes and other biochemical substances that regulate skin cell division are functionally imbalanced, thereby resulting in rapid proliferation of keratinocytes and incomplete keratinization. The expression of candidate genes such as E2A and caspase-9, which have been recognized to play a critical role in cellular proliferation/differentiation and apoptosis, is of great interest. They may be therapeutically targeted by the antipsoriatic drug, dithranol. We examined the molecular effects of dithranol on the mRNA and protein expression levels of E2A and caspase-9 in the HaCaT keratinocyte cell line. The HaCaT cells were treated with 0-0.5 μg/mL dithranol for 30 min. After dithranol was washed out, the HaCaT cells were cultured for 2 h, and their total cellular RNA and proteins were isolated. Quantitative real-time reverse transcriptase-polymerase chain reaction and Western blot were performed to determine the mRNA and protein levels of these two genes. We found that dithranol treatment in the range of 0.25-0.5 μg/mL slightly upregulated the mRNA expression of E2A and caspase-9 approximately 1.5- and 1.2-fold, respectively. However, undetectable change and minor downregulation of the protein expression levels were observed for E2A and caspase-9, respectively. Consequently, these genes appear not to be viable therapeutic targets for dithranol.

A comprehensive review of biomarkers in psoriasis

Psoriasis is a common, chronic skin disorder, the pathogenesis of which is incompletely understood. Results from various clinical and experimental studies indicate that psoriasis is a complex, multifactorial disease with a genetic predisposition. Factors such as climate, physical trauma, drug, stress and infections (Streptococcus, human immunodeficiency virus) are known to trigger psoriasis. The success of treatment of psoriasis with T-cell depletion and antitumour necrosis factor (TNF)-alpha treatment is explained by the involvement of T cells and TNF- alpha in the pathogenesis of psoriasis. The biochemical basis for the pathogenesis of psoriasis can be attributed to both overexpression and underexpression of certain proteins in psoriatic lesions. The anomalies in protein expression can be classified as abnormal keratinocyte differentiation, keratinocyte hyperproliferation and inflammation. Oxidative stress (OS) and increased free-radical generation have been linked to skin inflammation in psoriasis. The review presents evidence for various markers of psoriasis that can be targeted for effective treatment, including biomarkers of inflammation, keratinocyte hyperproliferation and abnormal differentiation, and stress.

Variable Bax antigenicity is linked to keratinocyte position within epidermal strata and UV-induced apoptosis

Pro- and anti-apoptotic members of the Bcl-2 family are fundamental in the control of apoptosis. Among them, Bax plays a key role in apoptosis induction by mediating the release of apoptogenic factors from mitochondria to the cytosol. In this report, we investigated, by immunohistofluorescence, the in vivo distribution of Bax in normal human epidermis before and 24 h after exposure to solar-simulated radiation. Bax expression was evaluated with three different, Western blot pretested, anti-Bax antibodies (Ab) and correlated with markers of keratinocyte differentiation and apoptosis using anti-beta(1) integrin and anti-active caspase-3 Abs respectively. Using anti-Bax N20 and A-3533 polyclonal Ab, we found that, whereas undifferentiated keratinocytes of the basal proliferative compartment contained Bax in the cytosol, the differentiated suprabasal cells had Bax mainly in the nucleus. This immunoreactivity pattern was not modified by skin irradiation. Interestingly, the well known apoptosis-related Bax redistribution to mitochondria in response to a cell death signal, could be detected only with yet another, the 2D2 monoclonal Ab. This relocalization occurred specifically in apoptotic, active caspase-3 positive cells of irradiated epidermis. Our data highlight the differentiation- and apoptosis-associated changes in the pattern of Bax subcellular and cellular distribution as uncovered by different anti-Bax Abs and suggest that Bax undergoes successive activation that progresses in parallel with keratinocyte differentiation and apoptosis.

Under-expression of VHL and over-expression of HDAC-1, HIF-1?, LL-37, and IAP-2 in affected skin biopsies of patients with psoriasis

BACKGROUND

A feature of psoriasis is the rapid proliferation of keratinocytes, during which apoptosis is blocked and angiogenesis starts. It is known that tumor hypoxic cells produce histone deacetylase-1 (HDAC-1), which up-regulates hypoxia-inducible factor-1alpha (HIF-1alpha) and down-regulates von Hippel-Lindau (VHL) protein by up-regulating vascular endothelial growth factor (VEGF) expression. It has been reported recently that the porcine peptide PR39 (homologous to human LL-37) has angiogenic and antiapoptotic activity. Thus, LL-37, induced by insulin-like growth factor-1 (IGF-1), could help in the production of VEGF. PR39 also induces the expression of inhibitor of apoptosis protein-2 (IAP-2), which blocks apoptosis. The purpose of this work was to analyze whether these genes and their proteins are expressed in psoriatic biopsies.

METHODS

Using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) messenger RNA (mRNA) expression and immunohistochemical staining, we studied VHL, IAP-2, and related genes in skin biopsies from psoriatic patients and healthy subjects.

RESULTS

An over-expression of the mRNA for HDAC-1, HIF-1alpha, LL-37, and IGF-1 in psoriatic skin, in comparison with skin from healthy subjects, was found. The antiangiogenic VHL mRNA and protein were under-expressed in psoriatic skin and highly expressed in healthy skin. The antiapoptotic IAP-2 was over-expressed in dermal endothelial cells from psoriatic skin. The pro-apoptotic Bax, Fas, and FasL mRNAs were expressed.

CONCLUSIONS

These findings suggest that there could be an association of HDAC-1, HIF-1alpha, LL-37, VHL, and IAP-2 with angiogenic and apoptotic mechanisms in psoriasis.

Examination of bcl-2 and p53 expressions and apoptotic index by TUNEL method in psoriasis

BACKGROUND

Psoriasis is characterised by hyperproliferation and by aberrant differentiation. Blockage of the normal apoptotic process is one of the factors implicated in the pathogenesis.

OBJECTIVE

To determine the apoptotic features by using TUNEL method and also bcl-2 and p53 expressions in psoriatic epidermis.

MATERIALS AND METHODS

Biopsies of 35 patients with psoriasis vulgaris and 14 normal skin were evaluated. Apoptotic cells were detected using the dUTP nick-end labelling assay; bc1-2 and p53 expressions were assessed by using immunohistochemical techniques. A semi-quantitative grading system (HSCORE) was used for comparison.

RESULTS

Bcl-2 was strongly expressed in basal keratinocytes of normal skin, while no expression was observed in 13 (37.2%) of the psoriatic samples and it was weakly expressed in the spinous cell layer of 22 (62.8%) samples. Moderate p53 expression was observed in the psoriasis group, while it was weak in the control. The percentage of TUNEL positive cells were significantly increased in the psoriasis group (65+/-2.30) when compared with the control (32.84+/-7.16).

CONCLUSION

Apoptotic index besides bc1-2 and p53 expressions in psoriasis differ from normal epidermis. Down-regulation of bc1-2 is consistent with the dynamics of psoriasis but increased TUNEL positive cells and p53 expression has not been fully elucidated yet. Gündüz K, Demireli P, Vatansever S, Inanir I. Examination of bcl-2 and p53 expressions and apoptotic index by TUNEL method in psoriasis.

Fas pulls the trigger on psoriasis

Fas/FasL signaling is best known for induction of apoptosis. However, there is an alternate pathway of Fas signaling that induces inflammatory cytokines, particularly tumor necrosis factor (TNF)-alpha and interleukin (IL)-8. This pathway is prominent in cells that express high levels of anti-apoptotic molecules such as Bcl-xL. Because TNF-alpha is central to the pathogenesis of psoriasis and psoriatic epidermis has a low apoptotic index with high expression of Bcl-xL, we hypothesized that inflammatory Fas signaling mediates induction of psoriasis by activated lymphocytes. Noninvolved skin from psoriasis patients was grafted to beige-severe combined immunodeficiency mice, and psoriasis was induced by injection of FasL-positive autologous natural killer cells that were activated by IL-2. Induction of psoriasis was inhibited by injection of a blocking anti-Fas (ZB4) or anti-FasL (4A5) antibody on days 3 and 10 after natural killer cell injection. Anti-Fas monoclonal antibody significantly reduced cell proliferation (Ki-67) and epidermal thickness, with inhibition of epidermal expression of TNF-alpha, IL-15, HLA-DR, and ICAM-1. Fas/FasL signaling is an essential early event in the induction of psoriasis by activated lymphocytes and is necessary for induction of key inflammatory cytokines including TNF-alpha and IL-15.

Vitamin D3 induces caspase-14 expression in psoriatic lesions and enhances caspase-14 processing in organotypic skin cultures

Caspase-14 is a nonapoptotic caspase family member whose expression in the epidermis is confined to the suprabasal layers, which consist of differentiating keratinocytes. Proteolytic activation of this caspase is observed in the later stages of epidermal differentiation. In psoriatic skin, a dramatic decrease in caspase-14 expression in the parakeratotic plugs was observed. Topical treatment of psoriatic lesions with a vitamin D3 analogue resulted in a decrease of the psoriatic phenotype and an increase in caspase-14 expression in the parakeratotic plugs. To investigate whether vitamin D3 directly affects caspase-14 expression levels, we used keratinocyte cell cultures. 1alpha,25-Dihydroxycholecalciferol, the biologically active form of vitamin D3, increased caspase-14 expression, whereas retinoic acid inhibited it. Moreover, retinoic acid repressed the vitamin D3-induced caspase-14 expression level. In addition, the use of organotypic skin cultures demonstrated that 1alpha,25-dihydroxycholecalciferol enhanced epidermal differentiation and caspase-14 activation, whereas retinoic acid completely blocked caspase-14 processing. Our data indicate that caspase-14 plays an important role in terminal epidermal differentiation, and its absence may contribute to the psoriatic phenotype.

Transgenic mouse models support HCR as an effector gene in the PSORS1 locus

Genetic susceptibility for psoriasis is regulated to the greatest extent by the PSORS1 locus. Three psoriasis-associated susceptibility alleles have been identified within it, namely, HLACw6, HCR*WWCC and CDSN*5, but strong linkage disequilibrium between them has made it difficult to distinguish their individual genetic effects, and animal models to study their effects are not known. To study the function of HCR, we engineered transgenic mice with either a non-risk allele of HCR or the HCR*WWCC risk allele under the control of the cytokeratin-14 promoter. These choices were motivated by the apparently dominant effect of PSORS1 on psoriasis susceptibility and the physiological expression of HCR in basal keratinocytes. Transgenic mice appeared phenotypically normal and histologically their skin was indistinguishable from wild-type mice. Expression studies using Affymetrix arrays suggested that the HCR risk allele has specific functional consequences relevant to the pathogenesis of psoriasis. Comparison of gene expression changes between non-risk and risk allele mice revealed similarities to previous observations in human psoriatic skin, including upregulation of cytokeratins 6, 16 and 17 in risk allele mice. We also observed changes in the expression of genes associated with terminal differentiation and formation of the cornified cell envelope. Our results support the concept that HCR may constitute an essential gene in the PSORS1 locus. These observations are also compatible with a model that a susceptibility gene for psoriasis induces changes that are contributory but not sufficient by itself to produce the clinical phenotype.